BIG BRO // Ryomen Sukuna
Summary: You are Itadori Yuji’s best friend and so close that you practically live in their house at this point. What started as a simple friendship turned into you overstaying and somehow never leaving.
But while everything feels easy with Yuji, it’s a completely different story with his brother, Sukuna. The two of you share a complicated friend-to-enemy dynamic, filled with tension that’s impossible to ignore. Especially when Sukuna himself is a walking sin that constantly tempting your once-innocent nature to cross lines you never thought you would.
Warnings: 18+, MDNI, NSFW, AGE-GAP, AU, HEAVY SMUT, explicit content, mature language, sexual innuendo, erotic, possessive, caught of jerking off, cum swallowing, mutual pining, heavy tension, ownership, lots of teasing, manhandling, petname, dirty talk, deflowering, degradation, oral activities, size difference, unprotected, PiV, squirting, spanking, fingering, blowjob, deepthroat, overstimulation, breeding, praising ,markings, rough sex, older man x younger woman
The summer heat clung to everything in the Itadori house like a second skin, thick and unrelenting. You kicked off your sneakers at the genkan the second you stepped inside while already calling out the familiar "Tadaimaaa!" even though this wasn’t technically your home. It might as well have been.
Jin’s warm “Okaeri!” floated from the kitchen and followed by the comforting clatter of a knife against a cutting board. You padded into the living room on socked feet while expecting to find Yuji sprawled on the couch with a manga or more likely half-asleep with his mouth open and drooling on the remote. Instead, your gaze snagged on broad shoulders with the black ink curling over tanned skin like spilled midnight, and the low, but lazy sprawl of Ryomen Sukuna occupying the entire sofa like he owned the damn planet.
He was wearing those stupid gray basketball shorts again, the ones that rode dangerously high on thick thighs whenever he shifted, and a black tank top so thin it might as well have been painted on. One arm was slung over the backrest while the other cradled a cold beer bottle against his abs.
The condensation dripped slowly down the glass and tracing a glistening path over one of the dark tattoos that wrapped his oblique. You hated how your eyes followed that droplet for half a second too long.
“ Oi, brat!” He drawled without looking up from his phone.
“ The stray kitten’s back.”
You bristled instantly. “ I have a name, asshole.”
“ Yeah. And I still don’t care.” Finally, those crimson eyes flicked up.
“ Are you gonna stand there gawking all day or actually come inside?”
“ I’m not gawking.” You snapped but your cheeks were already heating and your body was traitorous.
“ I’m looking for Yuji.”
“ He’s in the shower. Probably jerking off to that new idol PV again.”
“ Sukuna!” Yuji’s indignant yell echoed down the hallway before he even appeared while the towel slung around his neck and hair dripped pink strands onto his shoulders.
“ Stop saying gross shit to her!”
Sukuna smirked, slow and filthy. “ I’m just stating facts, brat. You’re the one getting defensive.”
You crossed your arms and tried to look unaffected. “ Whatever. I’m stealing your onigiri stash, Yuji.”
“ Already in the fridge.” Yuji grinned while trotting over to sling an arm around your shoulders like he’d done since you were both seven and he was still shorter than you.
“ Dad made extra salmon ones ‘cause he knew you’d show up.”
You leaned into him automatically and the easy familiarity ground you while Yuji smelled like citrus body wash and home.
Sukuna watched the whole exchange with half-lidded eyes, lips curling. “ Cute. Real domestic. You two gonna start braiding each other’s hair next?”
“ Jealous?” You shot back before you could stop yourself.
Big mistake.
The air changed when Sukuna set the beer down with deliberate slowness while his muscles shifted under skin like coiled pythons waking up. He rose and stalked toward you both with the lazy prowl of something that knew it was apex.
Yuji stiffened beside you. “ Hey. Back off.”
Sukuna ignored him completely. He stopped just close enough that you had to tilt your head back to meet his gaze. Heat rolled off him in waves like a summer sweat and cedar and something darker like something that made your pulse kick hard against your throat.
“ You're still so easy to rile up.” He murmured with his voice low enough that it felt private even with Yuji right there.
“ Look at you…already blushing like a virgin schoolgirl.”
“ I’m not…” Your voice cracked. Mortifying.
He leaned in another fraction and close enough you could count the silver ring in his bottom lip. “ Liar.”
Yuji shoved between you two so fast you stumbled back a step. “ I said back off, Sukuna!”
Sukuna’s chuckle was dark velvet. “ Protective little brother. How noble.”
Then, without warning, he hooked an arm around Yuji’s neck in a mockery of a headlock but gentle enough not to actually hurt and firm enough to make Yuji squawk.
“ Sukuna!”
“ Relax, pinky. I’m not gonna eat your precious best friend.” He ruffled Yuji’s wet hair hard enough to make him yelp, then shoved him sideways while Yuji’s shoulder clipped the wall with a dramatic thud.
“ Ow! You dick!”
You rounded on Sukuna as your fists clenched. “ You’re such a…”
He caught your incoming punch mid-air like it weighed nothing then fingers wrapping around your wrist. Not tight, just…there.
Your breath hitched when he tugged you forward one tiny step, but not enough to press you against him. Just enough to make you feel the gravity well of his body heat.
“ Careful, kitten.” He said softly and almost sweetly.
“ Keep swinging at me like that and I might start thinking you want my hands on you.”
Your mouth went dry.
Yuji was already scrambling back to his feet while whining. “ Sukuna, I swear—”
Sukuna didn’t look away from you. He lifted his free hand then his thumb brushing the center of your forehead in the lightest flick and a sharp sting bloomed instantly.
“ Ow!”
He released your wrist like he’d never held it at all and stepped back while smirking. “ See? Easy."
You rubbed the spot furiously and glaring murder, but your heart was trying to crawl up your throat and out your mouth.
Yuji grabbed your shoulders from behind and pulled you against his chest protectively. “ Stop being a creep to my best friend, you overgrown tattooed bastard!”
Sukuna rolled his eyes so hard it was audible. “ She’s not five anymore, idiot. She can handle a little teasing.”
His gaze slid back to you. “ Can you?”
You swallowed. “ I hate you.”
“ Yeah?” He tilted his head then his smile went razor-sharp.
“ Keep telling yourself that. Maybe one day you’ll believe it.”
He turned and sauntered toward the hallway while his broad back flexed under the tank top like he knew exactly what he was doing to you. At the threshold he paused then glanced over his tattooed shoulder.
“ By the way…” He added casually.
“ Next time you stare at my abs that long? I’m gonna start charging admission.”
Your face went nuclear.
Yuji groaned into your hair. “ I’m gonna kill him one day.”
You didn’t answer. Because beneath the embarrassment or beneath the fury like something hotter and more dangerous had taken root in your chest, and it had sharp teeth and crimson eyes and it was not going away anytime soon. Sukuna disappeared down the hall as the living room felt colder without him in it and you hated that most of all.
…
The late afternoon sun slanted through the living room windows in lazy gold bars while turning the dust motes into tiny fireflies. You were cross-legged on the floor helping Yuji sort through the mountain of takeout bags Jin had just dumped on the coffee table of karaage, yakitori, gyoza, tempura shrimp, and the works. The smell of hot oil and soy sauce was already making your stomach growl like an impatient dog.
Jin kicked off his work shoes at the genkan and padded in, loosening his tie with one hand. “ I’m home. I brought enough to feed an army or at least my three overgrown kids.”
Yuji perked up like a golden retriever. “ Dad! You’re the best!”
Jin ruffled his son’s hair, then glanced around. “ Where’s your brother?”
Yuji’s face soured instantly. “ He locked himself in his room after he shoved me into the wall and flicked her forehead like she’s a vending machine that ate his coin.”
Jin sighed, the long-suffering sound of a father who’d seen this movie a hundred times. He turned to you while his expression softened. “ Sorry about him, sweetheart. He’s got the emotional intelligence of a brick.
You shrugged and popped a stolen piece of karaage into your mouth. “ I’m used to it. He rage-baits me every time our paths cross. It’s basically his love language at this point.”
Jin barked a laugh.
“ You’ve got more patience than this one.” He jerked a thumb at Yuji.
“ These two fight over the dumbest things. Remember that time I came home and they both had black eyes?”
Yuji groaned dramatically while flopping backward onto the carpet. “ Dad, don’t…”
“ Tekken betrayal of the century.” Jin continued gleefully.
“ Sukuna beat him senseless in the game, and Yuji only realized halfway through that big bro was just mashing buttons against the CPU because the second controller wasn’t even plugged in.”
You choked on your karaage and the laughter bubbling up so hard tears pricked your eyes.
Yuji shot upright with his cheeks flaming. “ That was the worst betrayal in human history! I trusted him!”
“ You were twelve.” You wheezed.
“ It still counts!”
Jin chuckled while shaking his head. “ Stop acting like a kid, Yuji. You’re twenty-two now. It's time to be a man.”
You leaned over and stage-whispered. “ He still cries when Megumi and Nobara steal his last mochi.”
Yuji’s mouth dropped open in theatrical horror. “ I do not…okay, I did, but that was the last strawberry mochi of the day! They’re monsters! I love mochi more than I love them. It was worth the tears.”
You and Jin lost it completely while laughing until your sides hurt. Jin finally wiped his eyes and nodded toward the stairs. “ Go drag your Sukuna down here. Dinner’s getting cold, and the four of us are eating together whether he likes it or not.”
You froze mid-bite. “ Me? Why me? Yuji’s the younger brother. It's sibling jurisdiction.”
“ Yuji’s busy plating everything so it looks nice.” Jin said innocently.
“ You’re the only free operative.”
Yuji gave you puppy eyes and a thumbs-up. Traitor.
You sighed like a condemned prisoner and trudged upstairs but each step heavier than the last. Sukuna’s door loomed at the end of the hallway in black, imposing, and same as him.
You knocked three times. “ Oi, asshole. Dinner. Your dad’s orders.”
Silence.
You knocked again, harder. “ Sukuna, I swear…”
Nothing.
You pressed your ear to the wood. A faint, rhythmic sound is slick, wet, and unmistakable. Your brain short-circuited for half a second before you jerked back while your face was burning.
Nope. Nope nope nope. You were not hearing what you thought you were hearing.
You knocked one last time but still no answer.
“ Fine.” You muttered.
“ You asked for it.”
The knob turned easily. It's unlocked and a big mistake on his part.
You shoved the door open. “ Look, if you’re gonna sulk like a…”
The scream tore out of you before you could stop it. Sukuna was sprawled on his bed, completely naked, and sheets kicked to the floor. His hand was wrapped around his cock that was thick, flushed, and angrily hard and curved against the ridged plane of his abdomen while his tattoos snaked down his hips like dark promises.
His eyes snapped to you and wide with shock for maybe one entire heartbeat then he moved. He lurched off the bed so fast he stumbled while cursing under his breath. In two strides he was at the door then slamming it shut behind you and pinning you against the wood with the sheer size of his body.
One massive hand clamped over your mouth with the same hand that had just been—
Your eyes went huge because you tasted salt and skin and something musky that made your knees threaten to give out. He bent at the waist while keeping his erection from brushing your stomach, but close enough that you could feel the heat radiating off it.
His voice was low and gravel-rough. “ Scream like that again and the whole house hears. Nod if you’re gonna be quiet.”
You nodded frantically then he eased his palm away while you sucked in air like you’d been drowning.
“ Put…put some damn clothes on!” You hissed then slapping both hands over your eyes.
A low, dark chuckle as the fabric rustled. “ You can look now, princess.”
You peeked through your fingers. He's wearing his gray basketball shorts but still shirtless. His cock still visibly straining against the thin material like it had personal beef with gravity.
You dropped your hands and glared at the ceiling. “ What the hell were you doing?”
He leaned one shoulder against the doorframe while crossing his arms so his biceps bulged. “ What do normal men do when they’re alone and horny? Use your imagination.”
“ You’re disgusting.”
“ And you’re a pervert.” He tilted his head.
“ You were barging into my room without waiting for permission. What, are you part of some special task force now?”
“ I knocked! Three times!”
“ You should’ve waited like a good girl.”
You groaned then rubbing your temples. “ I’m not innocent anymore. Thanks to you and your…”
You gestured wildly at his crotch. “ That.”
He stepped closer. “ You’re still untouched and still innocent. You are just dramatic.”
You rolled your eyes so hard it hurt. “ Whatever. Your dad and Yuji are waiting. Dinner. All four of us. Move your ass.”
You turned to leave. His hand shot out, not grabbing your wrist this time, and just brushing the small of your back as you passed. You froze for half a second when he leaned down until his mouth was near your ear with his voice a velvet threat.
“ You just gave me the worst case of blue balls in recorded history, kitten. You interrupted me right at the edge.”
Your breath caught.
He continued. “ You owe me, and I collect debts.”
You shoved the door open and fled down the hallway without looking back while your heart was hammering so loud you were sure he could hear it. Behind you, Sukuna stayed leaning against the frame and watching the spot where you’d disappeared around the corner as he dragged a hand down his face while muttering a low and filthy curse.
“ Fuck.”
He glanced down at the tent in his shorts since he's still painfully hard.
“ Soon.” He promised the empty room.
“ You’re gonna pay that debt, and I’m gonna enjoy every second of it.”
Downstairs, Yuji called your name cheerfully while you forced a smile, sat at the table, and tried very hard not to think about the way Sukuna’s voice had curled around the word “soon” like smoke.
Dinner was going to be torture.
…
Days blurred into a sticky and uncomfortable haze after That Incident. You couldn’t unsee it and couldn’t un-remember. Sukuna’s cock had burned itself into the back of your eyelids with photographic cruelty. You’d be mid-lecture in class, pen hovering over notes, and bam, a flash of pink flesh slapping against tattooed abs. You’d flinch so hard your knee would bang the desk.
Today was no exception.
You, Yuji, Nobara, and Megumi were crammed around the low table in the school library’s group study corner while the textbooks splayed open like fallen soldiers. Midterms loomed like a guillotine. Nobara was viciously underlining kanji while Megumi stared at his notes like they personally offended him. Yuji was chewing the end of his pencil into splinters.
You were trying to focus on the quadratic formula when the memory hit again about the nine inches or more of shameless girth.
Your whole body jerked.
Nobara’s pen froze. “ The hell was that?”
Yuji blinked at you, wide-eyed. “ Are you okay? You look like you saw a curse.”
Megumi lifted one unimpressed brow. “ You’ve been doing that all week. What’s wrong with you?”
“ Nothing.” You squeaked, but voice cracking like a middle-schooler’s.
“ It's just…math. Math is scary.”
They all stared.
You buried your face in your hands. “ Shut up. Let’s just finish this chapter.”
The walk to Yuji’s house after school felt longer than usual. Every time a tall guy with broad shoulders passed by on the sidewalk, your heart lurched like it was trying to escape your ribcage while you kept your eyes glued to the pavement. When you finally stepped inside the familiar genkan, kicking off your shoes, the house smelled like laundry detergent and whatever Jin was simmering in the kitchen.
It's safe and normal.
Except Sukuna was there.
He lounged against the kitchen doorway in nothing but low-slung black sweats and a white wifebeater stretched tight across his chest with his arms crossed while watching you like a cat that had already eaten the canary and was debating dessert. His crimson eyes tracked every flustered twitch of your expression. He didn’t say a word but the slow curl of his mouth said everything.
You glared daggers. Don’t you dare.
He just tilted his head.
Yuji bounded in behind you. “ I gotta run back to school real quick…Nobara’s gonna skin me alive if I don’t give her that stupid pouch back. I forgot it in my locker earlier.”
You grabbed his sleeve. “ Hurry back, please.”
He grinned while ruffling your hair until it stuck up in every direction. “ I will! Ten minutes, tops. Don’t let Sukuna bully you too much while I’m gone.”
Then he was gone and the door clicking shut behind him.
Silence settled like humidity.
You huffed, dropped your bag by the couch, and flopped down at the low table where all your group project materials were still scattered from last weekend of construction paper, glue sticks, markers, and a metal ruler glinting innocently in the afternoon light.
You reached for it automatically while needing something to fidget with. The second your fingers closed around the cool metal when the memory slammed back.
A thick shaft measured against your horrified palm with Sukuna’s smug voice murmuring numbers like it was casual conversation.
You yelped and flung the ruler across the room like it had bitten you and it clattered against the wall until aheavy footsteps thudded down the stairs. Sukuna appeared at the bottom, step fresh from the shower while his hair damp and pushed back, and skin still glistening at his collarbones. A towel was slung over one shoulder as he looked down at you then sprawled on the floor clutching your chest like you’d been shot.
“ You look like shit.” He observed.
“ Shut up.” You hissed.
He ignored you completely and dropped onto the couch right beside you while the cushions dipped under his weight.
You shoved at his shoulder. “ There’s a whole other couch, you giant!”
He didn’t budge. He just smirked. “ I like this one.”
“ You’re not small enough to share it!”
His eyes glittered. “ I've never been small, kitten.”
Your face ignited. You smacked his bicep hard but his muscle barely flexed. He laughed and the sound vibrated through where your bodies touched then his gaze slid sideways and landed on the ruler you’d thrown. He reached down then picked it up with two fingers like it was evidence, and held it between you both.
“ Nine.” He said conversationally.
You choked. “ What?”
“ Nine inches.” He tapped the metal against his palm.
“ Thick and heavy when it’s hard. You already know.”
Heat roared up your neck. “ Why the fuck would you just…tell me that?!”
He shrugged. “ I figured you deserved the full specs as a friend.”
“ That is the most useless information anyone has ever forced on me.”
Another shrug. “ It will never be useless. One good shot of my swimmers and boom…someone’s knocked up. Biology lesson, free of charge.”
You hit him again harder but he just laughed louder.
“ I’m not lying.” He added, but softer now.
“ It’s nine. Wanna double-check?”
Your mouth went dry. “ I don’t believe you.”
Big mistake.
He chuckled and without breaking eye contact then hooked his thumbs into the waistband of his sweats and dragged them down just enough. His cock sprang free and already half-hard while slapping heavily against the white fabric still stretched over his abs.
You gasped so loud it echoed then your hands flew to cover your eyes. Sukuna caught your right wrist, gentle but unyielding, and tugged it down until your palm hovered an inch from the ruler he’d laid alongside his length.
“ Look.” He murmured.
You couldn’t not look.
The ruler’s markings lined up perfectly in nine inches or maybe a hair over. The girth made the numbers look almost comical. He released your hand as you jerked back like you’d been burned as he tucked himself away with casual efficiency while the waistband snapping back into place, then dropped his head against the couch cushions like he’d just finished reading the newspaper.
You stared at him with your mouth open as your brain short-circuited. “ You're a monster.”
He smirked without opening his eyes. “ Yes, my cock is a real monster.”
You shoved him again but he laughed then he cracked one eye open while his gaze sliding over your burning face and to your heaving chest.
“ I'm already hard again.” He said, but almost thoughtful.
“ I guess I’ll have to take care of it.”
Your breath hitched.
He stretched as his arms flexed and tattoos shifted like living shadows. “ I hope no one interrupts me this time.”
He stood and let you feel every inch of the space he’d occupied. At the foot of the stairs he paused, glanced back over his shoulder.
“ The door's unlocked...” He said.
“ If you get curious.”
Then he was gone as the footsteps fading up the stairs. You sat there while your heart was slamming against your ribs and thighs pressed together so tight they trembled. The ruler lay abandoned on the floor like a crime scene exhibit as you stared at it.
Nine inches and you were never going to survive this house.
…
The clock on the wall ticked past midnight and each second louder than the last in the quiet Itadori house. Yuji was dead to the world on the couch while his one arm flung over his face and soft snores rumbling every few breaths. The construction paper, glue, and half-finished poster boards littered the low table like the aftermath of a craft explosion. You rubbed your eyes, neck stiff, and stomach snarling like an angry cat.
“ Fine.” You muttered while pushing to your feet.
“ Snack break.”
The kitchen was dark except for the weak glow of the fridge light when you opened it as the cold air washed over your bare legs in your sleep shorts and an oversized tee you’d borrowed from Yuji years ago. You bent at the waist while rummaging past leftover karaage and a questionable yogurt and hunting for anything edible and quiet.
A shadow shifted behind you.
Before you could scream, a hard body slammed you forward and pinning your chest to the cold fridge door. One massive hand clamped over your mouth; the other braced beside your head and caged you in.
Your eyes flew wide.
A crimson and glowing faintly in the dim light.
Sukuna.
You shoved at his chest but it was useless but he didn’t budge.
He leaned in until his lips brushed your ear. “ Quiet, kitten. Wouldn’t want to wake the sleeping hero, would we?”
You wrenched your head sideways and voice a furious whisper against his palm. “ What the hell are you doing?”
He eased his hand off your mouth but kept you pinned. “ I'm hungry.”
You glanced back at the fridge contents. “ There’s…food. Right here.”
He groaned low in his throat, but the sound vibrated through your back. “ I'm not hungry for food.”
Your brows shot up. “ Then what…”
His gaze dropped to your mouth, then lowered before snapping back to your eyes. “ You.”
Your heart slammed against your ribs.
Before you could process, he spun you around then lifted you like you weighed nothing and slung you over his shoulder in a fireman’s carry.
Your yelp was muffled against his back. “ Sukuna, put me down!”
“ Shh.” He strode through the dark house then past the living room where Yuji snored obliviously, past Jin’s closed bedroom door, and out the sliding glass door to the backyard.
The cool night air hits your skin and the moonlight silvered the grass. He carried you to the far corner where an ancient ginkgo tree spread massive branches, its trunk thick enough to hide a small clearing behind it of his secret spot. A worn outdoor mat was already spread there like he’d planned this.
He dropped you onto it but not gently.
You scrambled to sit up, heart racing. “ What are you…”
His mouth crashed onto yours in hard, hungry, and no preamble. You shoved at his shoulders but the heat of him and the way his tongue immediately pushed past your lips made your arms tremble. He tasted like mint and danger while his tongue swept yours like he's claiming then sucked hard enough to pull a whimper from your throat. He broke away just long enough to spit into your open mouth. You choked with eyes wide, but he sealed his lips over yours again and forced you to swallow.
“ Fuck.” He growled against your lips.
“ I've been starving for this.”
He caught both your wrists in one hand and pinned them above your head. His free hand tilted your jaw and mouth descending to your throat. His teeth grazed skin then and the sharp sting bloomed into heat.
You winced, squirming. “ Ow!”
He sucked harder while marking you with wet, open-mouthed kisses, and leaving blooming red-purple bruises down the column of your neck. When he pulled back and satisfied with his handiwork, he hooked fingers into the hem of your shirt and ripped.
“ Hey!” You hissed but mortified.
“ That was…”
He laughed. “I’ll buy you ten more.”
Then his mouth was on you. His tongue flicked over one nipple while his fingers rolled the other. You arched involuntarily and a startled moan slipping free. The sensation was too much that made your eyes roll back. He switched sides by sucking hard enough to make your toes curl.
Then lower.
His tongue traced a slow, wet line down your stomach, and dipping into your navel that made you twitch. He shoved your shorts and panties down in one impatient yank then tossed them aside. You tried to close your legs but he wedged his shoulders between your thighs while spreading you wide.
“ Look at you…” He murmured.
“ Already dripping.”
Before you could protest, his mouth was on your cunt. He flattened his tongue and dragged it from your entrance to your clit in one long and sloppy stroke. Then he sucked your clit between his lips while flicking the tip of his tongue over it in rapid little pulses.
You cried out then slapped a hand over your own mouth. He groaned into you like he was devouring the sweetest fruit by slurping, sucking, and lapping at your slick like a man dying of thirst as the wet sounds echoed in the quiet night. Your thighs clamped around his head on instinct, heels digging into his back, and pulling him deeper. One hand released your wrist as the two thick fingers traced your slit while gathering wetness then pressed slowly inside.
You whimpered at the stretch.
He hushed you against your cunt. “ Relax, kitten. Let me in.”
He curled his fingers and searched until he found it. Your back bowed off the mat. A high and broken sound tore from your throat. He watched you the whole time as he pumped slowly while hitting that spot over and over.
The heat coiled tight in your belly.
“ Sukuna…” You gasped.
“ Cum for me.” He growled against your clit.
“ Give it to me. Your first one’s mine.”
He sucked harder and fingers crooked deeper.
You shattered as your back arched, thighs trembling, and a silent scream caught behind your teeth as pleasure ripped through you in blinding waves. Your walls fluttered and clenched around his fingers while the slick gushed over his hand. When the aftershocks faded, he pulled his fingers free and brought them to his mouth as he sucked them clean with a slow drag of his tongue. His eyes rolled back and a guttural groan vibrated in his chest.
“ Fuck.” He rasped.
“ It's the sweetest thing I’ve ever tasted.”
You lay there panting, dazed, thighs still shaking, body humming, and mind blank. He hovered over you, forearms braced on either side of your head, cock straining hard against his sweats, and a dark wet spot already blooming at the tip. Then he dragged the pad of his thumb over your swollen bottom lip.
“ We're not done yet., kitten” He murmured.
“ Not even close.”
Moonlight caught the sheen of your arousal on his chin while your heart was stuttered. Somewhere inside the house as Yuji snored, but under the ginkgo tree, the night felt endless and dangerously alive.
…
The night air was thick with the scent of ginkgo leaves and your own arousal still clinging to Sukuna’s skin. You lay flat on the outdoor mat, chest heaving, and thighs slick and trembling from the orgasm he’d ripped out of you. He hadn’t given you time to recover.
Instead, he rolled onto his side beside you and propped himself on one elbow while his crimson eyes dark and glittering in the moonlight. He watched you like a predator deciding which part to devour next. Then he shoved his sweatpants down just enough. His cock sprang free again and slapped wetly against the ridged plane of his tattooed abdomen.
The sound was obscene in the quiet backyard.
Your breath caught then he caught your wrist before you could pull away and guide your small hand to wrap around him. You gasped since he's so thick because your fingers didn’t meet while the vein along the underside throbbed against your palm like a second heartbeat.
Sukuna leaned in and lips brushed the shell of your ear. “ Give me a blow, kitten.”
Your eyes widened. “ I…I don’t know how.”
He chuckled. “ I’ll teach you.”
With easy strength he maneuvered you and settled you between his spread thighs. You knelt there with your face inches from his length while your heart was hammering so loud you were sure he could hear it. He gripped the base and playfully dragged the tip across your cheek, then laid it along the side of your face for comparison. The head reached past your temple when the shaft stretched longer than the width of your features.
“ Fuck.” He laughed.
“ It's still bigger than your whole damn face.”
He gave it a light slap against your cheek that made you whine.
“ Hey!”
“ Shh.” He thumbed your bottom lip and parting it.
“ Open."
You hesitated then obeyed as your lips parting on a shaky breath.
“ Good girl.”
He guided your head forward. You started with tentative kitten licks along the underside while tasting salt and skin.
Sukuna groaned. “ That’s not how you eat a cock, kitten. It’s not fucking ice cream.”
He fisted your hair but not hard enough to hurt, just enough to control and brought your mouth to the base.
“ Flatten your tongue and feel every vein.”
You did as you pressed the flat of your tongue against him and dragged up slowly, tracing the thick, and ridged lines. His hips twitched then another rough groan tore from his throat.
“ Like that.” He rasped.
“ Again.”
You repeated the motion but bolder now and mapping him with your tongue until he was leaking steadily against your lips.
He pulled you back to the tip. “ Open wider.”
You did.
He sank in when the fat head stretched your lips wide. You gagged almost immediately, throat fluttering, and eyes watering.
“ Breathe through your nose.” He murmured while his thumb stroked your cheek.
“ Relax your throat.”
You tried as you inhaled shakily through your nose when the scent of him filled your lungs. He started moving in shallow thrusts at first then letting you adjust and deeper. The lewd wet sounds of your mouth filled the night of glok-glok-glok every time he pushed past your soft palate.
Your hands braced on his thighs as your nails dug in. He pulled out just enough to let you gasp then slid back in. You gagged again harder when the tears spilled down your cheeks. He laid you flat on your back, shifted to straddle your chest, and knees bracketing your shoulders. One hand wrapped loosely around your throat while the other guided his cock back between your lips.
“ Look at me.” He ordered.
Your watery eyes met his then he thrust while watching the bulge form in your throat every time he bottomed out. The sight made his jaw clench and pupils blown wide.
“ Fuck.” He growled.
“ You take it so well.”
He picked up speed while the bulge appeared and disappeared rhythmically. Your throat worked around him, fluttering, and trying to accommodate. His grip on your throat tightened fractionally but just enough to feel your pulse racing under his palm.
“ I'm gonna cum.” He warned.
“ Swallow every drop. Not a fucking drop wasted.”
You whimpered around him as he slammed deep one last time then came. He's flooding your throat in heavy pulses. You swallowed reflexively, over and over, and your throat worked around the head as he groaned long and low. His hips jerked with each spurt until he was empty while twitching against your tongue.
He stayed there a moment, panting, and letting you feel the softening weight of him on your tongue. Then he pulled out slowly as the strings of saliva and cum connected your swollen lips to his tip. He swiped his thumb across your bottom lip, collecting what had escaped, and pushed it back into your mouth.
You sucked automatically while his eyes darkened further.
“ Good girl.” He murmured.
“ You took your first load like you were made for it.”
You lay there dazed, lips puffy, chin slick, throat raw, body buzzing, and mind blank except for the taste of him still coating your tongue. He dropped down beside you again then pulled you against his chest without asking while his one arm banded around your waist then he pressed a surprisingly gentle kiss to your temple.
“ Don’t think we’re done.” He whispered against your hair.
“ Not even close.”
Somewhere in the house, Yuji shifted on the couch and mumbled something incoherent in his sleep. But under the tree, your heart still raced like it would never slow down and Sukuna’s hand was already sliding possessively down your spine.
…
The night had cooled, but your skin burned where Sukuna touched you. You lay boneless on the mat while chest rising and falling in uneven pants then the aftershocks of your first orgasm still rippling through your core. He hadn’t moved far but he just shifted so he could watch your face and thumb brushing lazy circles over the fresh hickeys blooming across your collarbone. Then he hooked one of your thighs over his hip and spread you wider. Your breath hitched when you felt the blunt and hot head of his cock nudge your entrance again that slick with your release and his spit, but still impossibly thick.
You swallowed hard.
This was it. The line you’d never crossed. Your best friend’s older brother and the same man who’d spent years tormenting you with smirks and teasing words. Now, he was about to—
“ Sukuna…” Your voice came out small.
“ Maybe it won’t fit. You’re…you’re so big and I’m…”
He smirked, but his eyes softened a fraction and just enough to notice. “ Everything fits, kitten. Trust me.”
He dragged the head through your folds again while coating himself and teasing your clit until your hips jerked.
“ You’re gonna enjoy every fucking inch.”
He pressed forward as the thick head breached you while the insistent stretch that made your eyes water instantly. You whimpered with your nails digging into his shoulders, and bit your lip so hard you tasted copper.
“ Shh.” He murmured against your temple while his free hand cradling the back of your head and pressing your face into the crook of his neck.
“ Breathe, kitten.”
You sobbed quietly into his skin because you're too full already and he’d barely started. He stayed perfectly still while letting your walls flutter and adjust around just the head. Every pulse of your cunt seemed to pull him deeper and greedy despite the sting.
“ Fuck.” He hissed through clenched teeth.
“ You're so goddamn tight and sucking me in like you never want me to leave.”
After long seconds or maybe a minute, he felt the tension in your thighs ease the tiniest bit. He pushed another inch. You cried out while the fresh tears slipped down your cheeks.
“ Easy.” He soothed.
“ Pain’s gonna fade. I promise.”
He kissed your hairline, your temple, and the corner of your eye while his hips rocked in the smallest, shallowest thrusts, and coaxed your body to open. Then he sank the rest in one long and unrelenting glide. Your back bowed and a broken sob tore from your throat. You shoved weakly at his chest, overwhelmed, but he caught your wrists and pinned them gently beside your head, blanketing you with his weight, and keeping every inch buried to the hilt.
“ Shh, shh…I’ve got you.” He rasped while his lips brushed your ear.
“ You’re doing so good and taking all of me like you were fucking made for it.”
Your walls pulsed around him while trying to push him out and pull him deeper at the same time. You could feel him throbbing inside you while the head kissed your cervix. He stayed like that, unmoving, until your sobs quieted to shaky breaths. Then slowly he pulled back an inch and slid home again.
You whimpered. It still hurt, but underneath the sting something warmer was building. He set a careful rhythm by deep and measured rolls of his hips that dragged every ridge along your sensitive walls. Each thrust nudged that spot inside you until the pain began melting into something else entirely.
“ Fuck…there it is.” He growled when your hips lifted to meet him.
He shifted by rising onto his forearms so he could look down at you then watch your face while he fucked you slow and deep. He dropped his head, sinking his teeth into the soft skin of your neck again, and sucking a fresh bruise while his cock pistoned in and out. You clung to him while your nails raking down his back and leaving angry red lines across tattooed muscle. Every time he bottomed out you gasped and your thighs trembled.
The pain is gone now.
He pulled out suddenly and flipped you onto your stomach.
“ Ass up.” He ordered.
You obeyed on shaky limbs. He gripped your hair in gentle but firm, then tugged your head back so he could whisper against your ear while he slammed back inside from behind.
“ Such a perfect little cunt.” He growled while his teeth grazed your earlobe.
“ You were made to take my cock and listen to how wet you are…those filthy fucking sounds.”
Skin slapped skin in loud, rhythmic, and echoing under the ginkgo branches. He fucked you harder now, hips snapping, and balls slapping your clit with every thrust.
Then he stopped.
“ Stand up.”
You whined in protest but let him pull you to your feet on trembling legs. He spun you to face the tree trunk then bent you slightly forward and entered you again from behind but standing this time. The height difference forced you onto your toes. He lifted you easily with hands under your thighs, spreading you wide and fucked up into you with his brutal rolling thrusts. Your feet dangled. You were helpless, impaled, and bouncing on his cock while he held you like you weighed nothing.
The new angle hit deeper and harder and the heat coiled tight in your belly again but faster this time.
“ Sukuna…” You choked.
“ Yeah.” He grunted.
“ Cum with me. Milk me dry.”
A few more punishing strokes and you shattered as your walls clamping down so hard he cursed in loud and ragged. He slammed deep one last time and came then painting your insides while your own release pulsed around him. He kept you lifted while his cock still twitching and pumping the last of his release until nothing was left. When he finally eased out, a gush of cum and slick followed while dripping down your thighs in obscene rivulets. He turned you gently and his eyes dropped to his shaft then a thin smear of blood streaked the base.
He smirked.
“ First blood.” He murmured.
“ Mine.”
Then he lowered you both back to the mat and pulled you into his chest. His strong arms wrapped around you while one hand stroked your spine in long and soothing lines. You were exhausted since your limbs are heavy, mind fuzzy, and core still fluttering with aftershocks.
He pressed a kiss to the crown of your head. “ How was your first, kitten?”
You buried your face against his pec. “ I didn’t expect…it to be so tiring.”
He laughed. “ I'm glad you liked the performance. I’m legendary, y’know. Girls line up for this dick.”
You smacked his arm weakly. “ Stop. Don’t ruin the moment, you disgusting man.”
He chuckled again but softer this time, and caught your hand as he brought your knuckles to his lips.
“ I’ve tasted plenty of pussy in my life.” He said quietly.
“ But yours?” He kissed each finger.
“ This is the last one I’ll ever want. No one else. Just you.”
You froze.
He met your eyes. “ I mean it.”
Your throat tightened. Because you didn’t know what to say, so you just snuggled closer and tucked your face under his chin. He hummed in approval while his arms were tightening.
“ Sleep.” He murmured against your hair.
“ I’ve got you.”
Under the ginkgo leaves, moonlight filtering through in silver patches, you drifted off to the steady thump of his heartbeat against your cheek. For the first time in years, the house behind you felt far away while the man holding you felt dangerously and perfectly close.
…
The weeks after that night under the ginkgo tree felt like living inside a fever dream you couldn’t quite wake from.
Sukuna started texting the very next morning.
Oversized tattooed Gremlin: You alive, kitten?
Oversized tattooed Gremlin: Answer.
Oversized tattooed Gremlin: Now.
You stared at the screen in the homeroom, cheeks heating, and thumbs hovering. You typed Yes and hit send before you could overthink it.
His reply came in seconds.
Oversized tattooed Gremlin: Good girl. I miss your mouth already.
You nearly dropped your phone.
From then on, it was relentless.
Every day, good morning texts that sounded more like orders, random photos of his coffee mug captioned of ‘thinking of you choking on something hotter’, and voice notes of him growling your name just to hear how it sounded when he was half-hard and bored at work.
If you took longer than ten minutes to reply, your phone rang and rang until you picked it up.
The first time you let it go to voicemail, he called back-to-back six times. When you finally answered, breathless and hiding in the school bathroom stall.
“ Where the fuck were you?”
“ I was in class!”
“ Class ends. You don’t ghost me. Reply or pick up like a normal fucking person.”
“ You’re so dramatic.”
“ Says the girl who cried on my cock for the first time.”
You hung up. He called back immediately. You answered because apparently you were weak for crimson-eyed menaces now. He didn’t yell. He just breathed into the receiver like he was trying not to lose it.
“ Don’t do that again.”
“…Okay.”
“ Good.”
He hung up first.
It should’ve annoyed you. Instead your stomach fluttered every time his name lit up your screen.
At the Itadori house, nothing changed on the surface.
You and Sukuna bickered like always.
“ You’re taking up the whole couch again, you oversized tattooed couch gremlin.”
“ Move your tiny ass then, kitten.”
Yuji rolled his eyes. “ You two are worse than siblings.”
Jin just sighed and kept chopping vegetables.
But the second Yuji stepped out to grab soda from the konbini or Jin went to answer a work call, Sukuna moved. One second you were standing by the fridge, then the next your back was against the pantry door, his mouth on yours with hunger and bruising. He kissed like he was starving while tongue sweeping in, claiming, and tasting like he hadn’t seen you in years instead of hours. When he pulled back just enough to speak, his voice was wrecked.
“ I missed you, kitten.”
Your heart did something embarrassing and tripped, then soared.
“ You just saw me yesterday.”
“ It's too long.”
He kissed you again but slower this time and deeper until you were clinging to his shirt and forgetting how to breathe. Then footsteps in the hall as he stepped back like nothing happened with his expression cool and bored again.
You were still dazed and lips swollen, when Yuji walked in.
“ You okay? You look weird.”
“ I…um—yeah. Just…hot.”
Sukuna smirked behind Yuji’s back.
The pattern continued.
He sent bentos to your school of your favorite katsu curry. Once, a bouquet of white camellias arrived at your doorstep and your mom thought they were from Yuji and cooed about what a sweet boy he was. Sukuna corrected her politely when he showed up twenty minutes later to “walk you to the park.”
“ Actually, ma’am, they’re from me.”
Your dad blinked while your mom blinked harder.
“ Oh! Well…thank you, Sukuna-kun. That’s very thoughtful.”
He smiled and bowed slightly. “ My pleasure.”
You stared at him like he’d grown a third head.
Later, when your parents were inside and you two were alone on the porch swing, he pulled you onto his lap without asking. You went willingly and tucked yourself against his broad chest like he was a human furnace. He buried his face in the crook of your neck while he's inhaling deep.
“ You smell like me.” He murmured that almost purring while the vibration went straight down your spine.
“ You’re so clingy.”
“ Shut up. Real men don’t get clingy.”
“ Then what do you call this?”
He nipped your earlobe. “ Possessive.”
You shivered.
He loved marking you, but always in places clothes hid. The inside of your thigh. The curve under your breast. The back of your neck where hair covered the bruise. Each one a secret only he knew about when he peeled your clothes off later and he’d trace them with his tongue sometimes while murmuring praise against your skin.
“ Mine. All fucking mine.”
You never asked what “mine” meant. Because he hadn’t said it. There's no labels, no ‘girlfriend’, or promises spoken aloud. But his actions screamed. He walked you home every single evening he could and it didn't matter if he had late shifts at the garage. He’d wait outside your school gate while leaning against his motorcycle like some delinquent prince with his helmet under one arm.
Your classmates whispered.
“ Is that your boyfriend?”
You blushed. “ He’s…Yuji’s brother.”
“ Uh-huh.”
When you were alone he’d pull you between his thighs on the bike, kiss you stupid under streetlights, and hands roaming but never pushing past what you were ready for.
He is always waiting while you are content.
Because you trusted him.
The way he softened only for you. The way he carried you bridal-style up the stairs when your legs gave out after he’d made you come so hard you saw stars. The way he cleaned you up afterward with a warm cloth, pressing soft kisses to your temple while muttering, “You did so good for me.”
You were waiting for him to say it and to define it. Because every time he looked at you, you felt it like he wasn’t going anywhere.
One night, after he’d snuck into your room through the window like a criminal since your parents were asleep downstairs, he had you straddling his lap on your bed. You were hugging his neck while your face buried in his throat while he rubbed slow circles on your back.
He was quiet for a long time, not until he spoke.
“ You know I’m not good at this shit.”
You lifted your head. “ What shit?”
“ This.” He gestured between you.
“ Feelings, talking, or whatever the fuck we’re doing.”
Your heart kicked hard. He looked away and it was the first time you’d ever seen him avoid eye contact.
“ But I don’t want anyone else touching you and I don’t want to touch anyone else. Ever.”
You swallowed. “ Sukuna…”
“ I’m trying to do this right. For you.” He finally met your eyes.
“ I want you to be mine, officially. No more half-assed bullshit. You want that?”
Your throat closed up. “ Yes.”
He exhaled like he’d been holding his breath for weeks then he kissed you and it's different from the hungry ones.
This one felt like a vow.
When he pulled back, his forehead pressed to yours.
“ Girlfriend. You’re my girlfriend now. Say it.”
You smiled through blurry vision. “ I’m your girlfriend.”
He grinned but soft around the edges. “ Good. ‘Cause I’m not letting you go.”
You snuggled back into his chest with your arms tight around him as he purred again. And for the first time since that night under the tree, everything felt…settled. It's not perfect. It's still messy, still full of bickering, secrets, and stolen kisses.
But yours.
Finally, undeniably yours.
