you and your boyfriend playing who can seduce nerd!armin arlert first ╱ mdni. lots of sex. reader and jean are freaked out and whipped, armin's a perv but doesn't want to admit it. wc: 2.5k ˚.✦
Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Bonus
"Haah, s'good baby so so mmph!" Your back arches off the bed, Jean's free arm pinning you back to the mattress in one slip motion.
You can feel the smile on his face as he goes back at your clit, sucking in lightly, circling his tongue around it without enough pressure. You tangle your hands in his hair, trying to push him deeper into you but the motherfucker is strong enough to just moves exactly how he wants to.
"Jeaaaan," you moan, dipping your head back with a groan.
He's been lapping at your folds for fifteen minutes already, you're sweaty and a little drunk from the few drinks you shared downstairs. Your boyfriend is lost in the way you taste and in the way you flutter.
Jean hums against you in response, the low vibration shooting straight through your core and making your thighs twitch around his head. He doesn’t give you what you’re begging for. Instead he flattens his tongue and drags it slowwwly from your entrance back up to your clit, collecting every bit of you like he’s savoring something rare.
“Goddamn, listen to you,” he murmurs. “Sound so fuckin’ pretty when you’re this needy, baby. You know that?”
You try to answer but it comes out as a broken little whimper. Your fingers twist tighter in his hair just holding on for dear life. He lets you tug this time, but only enough to tilt his head the exact angle he wants before he seals his mouth over your clit again.
This time he sucks harder.
Your hips jerk up involuntarily and he groans like you just handed him heaven on a plate. The arm he has banded across your lower stomach flexes, keeping you pinned exactly where he wants you while his free hand slides up the inside of your thigh, fingertips brushing the sensitive skin there before two of them nudge at your entrance.
“Relax for me, pretty girl,” he coaxes, voice muffled and filthy against your cunt. “Wanna feel how tight you get when you’re this close.”
You’re already fluttering around nothing, so when he finally pushes both fingers in, curling them just right, you nearly sob. He crooks them against that spot inside you at the same time his tongue flicks fast little circles over your clit and the combination rips a loud, wrecked sound out of your throat.
“Thaaat’s it,” he praises. “There she is. My good fuckin’ girl. Gonna come all over my face, yeah? Wanna feel you soak me.”
The rhythm turns filthy—sucking, licking, curling, thrusting—relentless but never rushed, like he could happily stay between your legs until the sun comes up. Every time your hips try to chase more he simply presses you back down reminding you who’s in control.
“Jean, please fuck fuck fuck, I’m—” Your words fracture into gasps. Heat coils so tight in your belly you can barely breathe. Your legs shake, toes curling against the sheets.
He knows. Of course he knows.
He pulls back just enough to speak against your dripping folds, breath hot and voice gravel-rough. “Go on, baby. Come on my tongue like you’ve been dying to all night.”
Then he dives back in. Sucking your clit into his mouth hard, fingers pumping faster, curling deeper.
Your back bows off the mattress again, a broken cry tearing out of you as you come hard, pulsing around his fingers, gushing against his tongue. Jean doesn’t stop. He works you through every shuddering wave, licking slower now, softer, drinking down every last bit of you like he’s starved for it.
When you finally collapse, trembling and gasping, he eases his fingers out gently and presses one last open-mouthed kiss to your oversensitive clit that makes you twitch and whine.
He crawls up your body slow, kissing every inch of skin he passes. Your stomach, the underside of your breast, the hollow of your throat. Until he’s hovering over you, forearms braced on either side of your head.
His mouth is glossy, chin wet, hair a complete mess from your hands. He looks wrecked in the best way.
And he’s smiling like he just won something.
“Look at you,” he murmurs, brushing sweat-damp hair off your forehead before leaning down to kiss you deep and lazy, letting you taste yourself on his tongue. “So fuckin’ perfect when you come for me.”
"Mmhm," is all you manage to say, closing your eyes from exhaustion.
Jean squints his eyes, noticing something on you right away. "You're quiet today."
"Am I?" You open your eyes, looking at him right in his.
He lets himself rest beside you, head on his palm while the other plays with your nipples. He's always loved feeling them harden in his fingers, kneading your breasts as you're speaking about the most mundane things.
"Yup. You're usually waaay louder." He shrugs his shoulders, taking one of your curls and curling it tighter between his fingers.
"Well, there's at least 30 people downstairs, I don't want 'em to hear me whine for Jean fucking Kirstein," you shoot back, arching your eyebrows with a teasing smile.
He rolls his eyes, not falling for the bait and leaning closer to you. "You're thinking about something, I know it. Jus' tell me what it is."
Jean nuzzles deeper into the crook of your neck, lips brushing the sensitive spot just below your ear.
“You’re doing that thing again,” he mumbles against your skin. “The one where your brain goes somewhere else and you forget I’m right here.”
You huff a small laugh, threading lazy fingers through his damp hair. “I’m literally naked under you, Jean. How could I forget?”
“Doesn’t mean your head’s here.” He pulls back just enough to look at you. Hazel eyes narrowed, searching. The playful edge is still there, but there’s something sharper underneath it now. “Spit it out, baby. You’ve been weird since we came up here.”
You bite the inside of your cheek, debating. The post-orgasm haze usually makes you loose-lipped and honest, but this feels… different. Riskier.
He waits. Patient. Thumb still idly circling your nipple like he’s got all night.
You exhale through your nose. “Okay. Fine. But don’t freak out.”
His brows lift. “Now I’m definitely freaking out.”
You roll onto your side to face him properly, sheets tangling around your hips. “It’s stupid. Probably nothing.”
“Try me.”
Another beat of silence.
“…I’ve been thinking about Armin.”
Jean goes very still. Not angry-still. Just… processing-still. The hand on your breast pauses mid-motion.
“Armin,” he repeats slowly, like he’s tasting the name. “Arlert. The blond one with the glasses who volunteers at the library?”
You nod, small. “Yeah.”
Jean’s jaw flexes once. He sits up a little, leaning on one elbow so he’s looming just enough to make the air feel heavier. “And you’re thinking about him… while I’ve got my tongue buried in your pussy for the last twenty minutes?”
The bluntness makes heat crawl back up your neck. You don’t look away, though. “Not the whole time. Just… lately. In general.”
He lets out a short laugh that doesn’t quite reach his eyes. “Jesus. Okay. Wow.”
“You asked.”
“I did.” He drags a hand down his face, then back through his hair, making it stick up worse. “So what? You want him? Like… want want him?”
“No. Yes? I don’t know.” You sit up too, pulling the sheet over your chest like it’ll protect you from how exposed you suddenly feel. “It’s not like I’m gonna go jump him tomorrow. It’s just… I’ve noticed things.”
Jean’s stare is steady. “What things.”
You swallow. “The way you look at him sometimes.”
That hits. His expression flickers.
“Excuse me?”
“Come on, Jean.” Your voice softens. “In class. When he’s explaining something and the whole room shuts up to listen? You watch him like… like you’re trying to figure out how someone can be that smart and that pretty at the same time.”
“I do not.”
“You do.” You reach out, brush your fingertips along his jaw. “And it’s hot. The way your eyes get all dark and focused. Like you wanna pin him to the nearest wall and see if he blushes as pretty as he talks.”
Jean’s throat bobs. He doesn’t deny it.
After a long second he mutters, “Fuck.”
“Yeah.”
He flops onto his back, staring at the ceiling. One arm thrown over his eyes. “This is so fucked up.”
“Is it?” You crawl over him, straddling his hips. The sheet falls away. His hands automatically settle on your thighs (habit, muscle memory) but he doesn’t move otherwise. “Or is it just… honest?”
He peeks at you from under his forearm. “You’re really sitting here, fresh off coming on my face, telling me you’ve got a crush on the nerd boy I’ve also been lowkey eye-fucking in lecture hall?”
You shrug one shoulder. “Maybe we both do.”
Silence stretches.
Jean’s hands flex on your thighs. Not pushing you off. Not pulling you closer. Just… holding.
“You’re serious,” he says finally. Quiet.
“I think so. Yeah.”
He exhales hard through his nose. “He’s so fucking quiet. And polite. And he smells like new books and vanilla or some shit. It’s infuriating.”
You smile despite yourself. “You’ve noticed how he smells?”
“Shut up.” But there’s no heat in it. His thumbs start slow circles on your skin. “He’s got those stupid long lashes. And when he pushes his glasses up? I wanna bite something.”
You laugh. “Jean Kirstein admitting he’s got a thing for the soft boy in the front row. Never thought I’d see the day.”
He glares, but it’s half-hearted. “Don’t get cute. You started this.”
“I did.” You lean down, forearms braced on his chest, faces close. "But it's not like we can do something about it."
Jean let your phrase sit for a couple of seconds. "How do we even approach someone like that?"
"He probably thinks it's a bet or some fucked up shit like that," you add, biting your lips.
"He might not even like boys," Jean says.
You arch your eyebrows immediately, blinking fast.
"He might not even like girls," Jean fixes, shrugging his shoulders.
He lets out a frustrated groan, tipping his head back against the pillow.
You trace lazy patterns across his chest with one fingertip, feeling the steady thump of his heart under your palm. “We could just… not do anything. Keep it as fantasy. Make love to the mental image and call it a day.”
He snorts. “Yeah, because that’s worked so well for the last month. You’ve been zoning out mid-makeout thinking about him, and I—” He cuts himself off. “I caught myself staring at his fucking hands in seminar last week. Hands. Who gets hard over someone’s knuckles and a fountain pen?”
You bite back a grin. “You do, apparently.”
“Fuck off.” But he’s fighting a smile too. His hands slide up your thighs to your hips, squeezing once like he’s grounding himself. “Seriously though. If we’re gonna do this, we gotta be smart. He’s not the type you just corner at a party and proposition. He’ll bolt like a startled deer.”
“True.” You sit up straighter, straddling him properly now, the sheet pooled around your waist. The cool air makes your skin pebble, nipples tightening again under his absent gaze. “So maybe we don’t do it together. At least not at first.”
Jean’s brows knit. “What, like… take turns?”
“Exactly.” The idea sparks behind your eyes, wicked and fun and just competitive enough to make your pulse kick up again. “We approach him separately. Feel him out. See if he bites. No pressure, no tag-team bullshit that’ll scare him off. Just… normal conversation. Flirt a little. See who gets further.”
Jean’s mouth twitches. “You’re turning this into a game.”
“I mean…” You lean down until your noses brush, lips hovering over his. “Aren’t you competitive?”
His pupils blow wide. “You’re evil.”
“Say the word and we drop it.”
He’s quiet for a beat. Then his hands clamp down on your hips, dragging you forward so you’re seated right over the thick ridge of him.
“Rules,” he rasps.
You grin against his mouth. “I’m listening.”
“No lying to each other. Full disclosure after every interaction. What you said, what he said, how he looked at you, if he blushed, if he got flustered, if he touched you even by accident.”
“Done.”
“No sabotaging. If he picks one of us, the other backs off gracefully. No guilt-tripping.”
You nod. “Fair.”
“And” His voice drops, rougher now. “If he’s into both… we talk about bringing him in together with no rush.”
Heat pools low in your belly again. “God, yes.”
Jean’s thumb brushes the crease of your thigh, teasingly close to where you’re still slick and sensitive. “One more. Winner gets to call the shots the first time we’re all three together. If it gets that far.”
Your breath hitches. “You’re so on.”
He smirks, slow and dangerous. “Oh, baby. You have no idea how bad I want to watch that pretty boy fall apart under you while I tell him exactly how to touch you.”
You rock down against him once, just to hear him curse under his breath.
“So,” you whisper, lips grazing the shell of his ear. “Who goes first?”
Jean thinks for a second, eyes flicking over your face like he’s calculating odds. Then he shrugs one lazy shoulder.
“You go tomorrow. He’s always at the library after third period, right? Buried in some ancient philosophy text or whatever.”
You nod. “Yeah.In the same spot as well, thinks no one notices him.”
“Cute.” Jean’s hand slides up your spine, fingers threading into your hair so he can tug your head back gently and kiss the column of your throat. “Wear that skirt you know he stares at when he thinks you’re not looking. Bend over to pick up a book or something. Give him something to think about tonight when he’s jerking off in his dorm.”
You laugh, breathless. “You’re awful.”
“I’m strategic.” He nips your pulse point. “I share a class with him on Wednesday, I’ll sit next to him. Ask him to explain some bullshit concept I already know. Maybe brush our knees under the table. See if he startles or leans in.”
The mental image makes you clench around nothing. “You’re gonna make him stutter, aren’t you?”
“Fuck yeah I am.” Jean’s grin is feral now. “And every time he pushes those glasses up? I’m gonna picture them fogged up later.”
You moan softly, grinding down again. “This is gonna be torture.”
“Good torture.” He flips you onto your back in one smooth motion, pinning your wrists above your head. His mouth finds yours, tasting like victory already. When he pulls back, his voice is wrecked. “You better tell me everything tomorrow night. Every single detail. How red his ears got. If he adjusted his pants. If he looked at your mouth when you talked.”
“Promise.” You hook a leg around his waist, pulling him closer. “And you better do the same.”
Jean rocks against you slow, deliberate. “Deal.”
He kisses you again, harder this time, all teeth and tongue and barely restrained hunger.
“Get some sleep, baby,” he murmurs against your lips. “You’ve got a nerd to seduce in the morning.”
You smile into the dark, heart racing.
“And you’ve got one hell of a competition on your hands, Kirstein.”
He chuckles low in his throat, already sliding down your body again, mouth trailing fire.
“Bring it.”
a/n: idk when this came to life but i love this kind of trope in fanfics
