✧ TUTOR — lhs
SYNOPSIS — when what was supposed to be a tutoring session with your older brother's best friend turns into him fucking you raw in his room.
pairing ꣑୧ brother's bsf!heeseung x f!reader
warnings ꣑୧ smut with plot (MDNI!), unprotected sex (be safe irl), dirty talk, oral (f receiving), mention of body image, slight breeding kink (?), praising, overstimulation (multiple orgasms), idk they're down bad for eo . . .
WORD COUNT: 3.7k ❀˖°
you've known of heeseung since forever. even when you were young and was still sharing a room with your brother jake. your brother would say his name while playing online games, but you didn't really know who he was. you didn't pay attention to him and he held no significance to you since he was just your brother's friend.
until he wasn't.
it all started about a year ago, during a family dinner when your mom suddenly blurted, "yn, what if one of jake's friends became interested in you?"
you choke on your food. caught off guard, you furrowed eyebrows in confusion.
of course, jake was even more confused. he scoffed after letting out an airy laugh, thinking it was ridiculous. he didn't take it seriously and you didn't either.
"what the heck, mom? they're jake's friends.. that's weird."
"so?" your mom giggled. "heeseung is not so bad. he's a kind boy, plus your dad and i already know him so that saves the whole awkward parent—boyfriend meetup."
"oh my god," jake rolled his eyes after hearing his best friend getting mentioned.
she wasn't being serious. or was she? you were confused but you laughed it off, thinking it was only a silly joke that wouldn't escalate.
but her words stuck to you.
ever since your mom teased you about heeseung, you found yourself curious so you took every chance you could to see him.
every spontaneous hangout that jake had with his friends, you would go. and every time you did, you noticed how goddamn attractive heeseung was.
sometimes, he looked unfairly good for how simple his outfit was—a black shirt with some sweatpants. there was nothing flashy about it, but that was the point. he didn't need anything else to look good. the simplicity made him look even finer, like he was effortlessly confident in the quiestest way possible.
it wasn't only his looks that made him incredibly attractive. in fact, you found his personality adorable. he was a nerdy guy who liked to play video games and also play sports—especially basketball and god, he was so good at it. you also witnessed how amazing of a singer he was when you all went to a karaoke one time.
it wasn't uncomfortable hanging out with jake and his friends despite the fact that they were all older than you. most of them just saw you as a little sister.
and you thought heeseung thought the same.
but you were so wrong.
you thought you were delusional when heeseung would be the only one out of everyone in the group to talk to you sometimes.
you thought you were delusional when you would glance at him and his eyes were already on you.
you thought you were delusional when you felt that tension every time you were in the same vicinity as him.
you thought it was only you who felt this way.
most of the time, the rest of the guys would simply wave at you and forget your presence afterwards, which was fair because it's not like you were close to them.
but heeseung? he always took his time asking you about your day and talking about random things with you.
today, you joined him and jake at the gym since you were planning to go anyway, so the three of you worked out together.
jake went ahead to finish his final set of the first workout, leaving you and heeseung just standing off to the side, resting before you both finish your own sets.
"so, how long have you been going to the gym?" he broke the silence, his deep voice lingering inside your ears.
"uh, couple months. but i'm on and off with it." you replied nervously. every interaction with him made your stomach do flips and you didn't wanna mess it up each time.
"ahh i see. there's nothing wrong with that, we all start somewhere. what's your main goal? is it building muscle or like, achieving your dream body kinda?" he raised his eyebrows, genuinely curious.
"mm.." you took a second to think before he gave you a warm smile. you almost fainted from that damn smile.
"a little bit of both i guess. my arms are weak so i want them stronger in general, but i also want my body to look nicer." you answer truthfully.
he blinked slowly before scanning your body up and down. your cheeks turned flushed pink before he quietly said, "your body's already real nice though."
"oh t-thanks," you laugh awkwardly, not knowing how to react to the sudden compliment.
"anyway," he looked around the gym, realizing he was flustered too. he was always nervous when talking to you too, he was just better at hiding it. the last thing he wanted was to make you feel uncomfortable.
"you're in uni now right? what's your major?" he switched the topic.
"i'm a biology major-"
"no way, i am too." he immediately turned his head towards you. his eyes widened, pleasantly surprised that you two shared something like this in common. his bambi eyes melted you and you almost forgot what you guys were talking about.
"wait really, oh my god! are you in your fourth year then?" you were also happily shocked hearing this. multiple thoughts crossed your mind.
he must've already taken the classes that you're currently taking and you started to wonder if he got good grades. knowing the fact that heeseung was good at everything, he probably did well in academics too.
"mhm, so you're probably in your second year. if you need notes or help or anything, just let me know. i'm always at your place anyway cause of jake. i could always tutor you- well only if you want." he got embarrassed when he realized he'd been rambling and stopped.
you gulped at the thought of heeseung tutoring you. you know for a fact you wouldn't be able to focus if it was him tutoring you.
"that would be amazing," you smile and he suddenly takes his phone out and hands it to you. you blink up at him, confused.
he chuckles, "put your number in. you could always text me if you're struggling with anything," he puts his hands in the pockets of his sweatpants as he watches you put your number into his phone.
it was pretty similar with heeseung. he had known of you for years but you weren't significant to him. you were just his best friend's younger sister throughout these years.
however, he recently started seeing you differently as well. it was a couple months ago when a going-away party for some guy named sunghoon—one of jake and heeseung's friends—took place.
you hadn't planned on going, but it was a pretty big party and you heard your brother jake was going, meaning his friends were going too—although you really only wanted to go there to see heeseung. you haven't had the chance to see him in a while so you knew you had to go. previously, he never showed special attention towards you so on the day of the party you decided to look your best for him, hoping he could notice you.
"whatever yn, just don't get black out drunk tonight please," jake sighs, wondering why he even let you come with him.
you wander around the place on your own, eventually stumbling across the kitchen where you find the drinks. you go and reach for one but a hand grabs the drink you were reaching for first.
"hey-" you stop when you look up and see that it was heeseung.
he too, was simply trying to get himself a drink but didn't see that you were reaching for it. he was about to apologize when he laid his eyes on you, unaware that it was you—jake's younger sister.
he remained standing there with the drink in his hand, almost stunned just by looking at you. his eyes wandered from your face to your hair, then to your body, scanning the bodycon dress that you were in.
holy fuck she's gorgeous. he thought, still not registering in his mind that it was you. he was lost in his thoughts now while clearly checking you out, failing to realize that he was biting his bottom lip at the sight of you.
he came back to his senses when jake puts his arm around his shoulder and jokingly says, "yo heeseung, you babysitting yn for me?"
shit. that's yn? he couldn't believe it. he had no idea you looked like this now.
heeseung awkwardly chuckles, "nah, just pouring her a drink." he pours a shot for you and you take it. both heeseung and jake were shocked at how you drank it with no hesitation.
this was the exact moment heeseung realized that you were no longer just his best friend's sister. that you were someone who made him feel things.
so the fact that he now had your number and a reason to see you apart for being with jake, he felt ecstatic.
you don't even feel tired when you get home despite the fact that you worked out a lot today. all you could think about was how you had heeseung's number and a chance to see him alone.
you stare at the contact on your phone. heeseung lee.
you start pondering, debating on whether to text him or not. not long after, you pick up your phone and send him a text.
heeseung lee
me: hi heeseung ! [9:46pm]
heeseung lee: heyy yn what's up [9:48pm]
me: i was just wondering if u could help me with anatomy? i completely forgot to study and my midterm for it is the day after tomorrow.. [9:52pm]
heeseung lee: ofc yn i could help u [9:53pm]
heeseung lee: wanna come over instead? i kinda told jake i wasn't available today so he might find it weird if i go there to tutor u but not hang w him ykwim? [9:54pm]
me: oh omg if ur busy today then don't worry about it it's fine !! [9:58pm]
heeseung lee: nono pls come [9:58pm]
heeseung lee: i only said no to him bc i felt slumped this morning lmao [9:59pm]
me: are u sure? i rlly don't wanna bother u.. :( [10:03pm]
heeseung lee: i promise i'm sure yn, come over rn yk where i live [10:04pm]
me: okie i'll be there in 15 ! [10:06pm]
heeseung lee: see u yn :) [10:07pm]
truth is, your anatomy midterm was last week and you in fact did not need any help. instead, you had a chance to see him and you took it.
it must've only been 10 minutes and you were already there standing in front of his door. he lived nearby and you didn't wanna come later than the time you said you were going to arrive, plus you were always the type to be early anyway.
heeseung jumped out of his seat and quickly fixed his hair in the mirror before leaving his room to open the door for you.
his tall figure was now standing there in front of you and you couldn't help but feel nervous. after all, it was your first time seeing him without being with jake. you had a clear motive tonight and it definitely was not to be tutored by him.
he smiles, "hi yn. come in," you walk into his apartment, looking around.
him wearing an oversized white tee and grey sweatpants made you go absolutely insane on the inside.
"here let's go to my room," he leads you to his room and you follow. his room was clean but in that lazy, lived-in way that felt comfortable instead of perfect. the bed was made, although the blanket was pulled up loosely, wrinkled in spots he hadn't bothered to fix.
a grey hoodie was draped over the back of his gaming chair, not tossed but not folded either, like he just slipped it off a moment ago.
his whole room carried a faint, comforting scent of laundry and him, like it was kept neat enough to be welcoming without losing its softness.
he follows you after you enter his room, carefully closing the door behind him.
he forgets what you came there for when he sees you you sit down on his bed with that adorable skirt that was definitely too short for a tutoring session.
did you purposely wear a revealing outfit? yes. and did it work on him? absolutely.
"so, what did you need help with again?" he rubbed the back of his neck, glancing at your thighs.
he couldn't stop thinking about how you were on the same bed that he gets off of while thinking about you.
"anatomy.. what else..?" you replied in a teasing tone then crossed your legs, fully aware of the fact that your skirt was too short to cover the sides of your ass whenever you did this.
he knew what you were doing. the atmosphere in the room suddenly changed and he slowly started walking towards you, his eyes never leaving yours.
he was now standing before you, carefully leaning down at you. you lean back and he places both hands by your sides, looking directly into your eyes.
at this point, his face was inches away from yours.
"no yn, what did you really come here for?" his eyes were now full of need. he needed a clear answer for you.
his mind was going insane. he wasn't sure if he was imagining all of this, since these situations only happened in his imagination anyway.
you look up at him with your doe eyes before quietly saying, "you."
he squints his eyes, "didn't hear you. say it again?"
"you. came here for you," you gave him a slight smile.
"i love how you listen to me so well," he caressed your cheek before adding, "can i?" he was so soft spoken it turned you on even more.
"you don't even have to ask, hee."
and that's all it took for him to crash his lips onto yours. he kissed you deeply, slow at first but deliberate and with purpose. you lay your back on the bed and he now hovers over you, not breaking the kiss.
his hands roamed all over you, touching every part of you like he'd been wanting to.
you lightly push him back to try and take your top off. he notices this and takes it off for you instead and you hear him whisper a "fuck." under his breath when he sees you topless. he slips his shirt off as well and leans down to kiss you once again.
now your hands were roaming all over his chest, his abs, his arms, his shoulders, everywhere. the kiss was rougher now, both of you getting impatient.
he pulls back to breathe, "been wanting to touch you like this for a while,"
he started leaving kisses on your jawline, then he moved down to your neck, then to your collarbone. he was doing all of this while massaging your breasts and you could feel your wetness pooling at this point.
he starts sucking on one of your breasts, gaining a whimper from you. "want you right now, hee."
he hums against you, "not yet baby,"
he leans up and pulls your skirt down, leaving you exposed in your panties. as if the skirt even covered anything. he cups your clothed cunt, "oh my god," you whine.
"shit.. so wet. all this for me?" he smirks as he finally takes your panties off. you nod as he spreads your legs, "you're so pretty," he says and you immediately get shy and try to close your legs, but he held them open.
he started to leave kisses in your inner thigh, your cunt clenching onto nothing from this teasing feeling.
he notices how you were squirming and decided to finally rub your wet clit in a circular motion.
he positions himself between your legs and licked a stripe up your pussy, gaining a loud moan from you.
"taste so good i could stay here forever baby," he hummed against you, sending vibrations all throughout your body.
he was already obsessed with your taste. he was doing this not just to please you but himself as well. he felt his cock throbbing in his pants as he continued lapping at your cunt.
he fastened his pace and started rubbing your clit with his thumb once again. "f-fuck oh my god," you grab onto his hair frantically and he whimpers from you doing this.
"oh god heeseung, i'm gonna-" your hips bucked, pushing yourself into his mouth further when he pulled away and rubbed your clit harder than before.
"cum for me, my perfect girl." he bit his lip at the sight of you reaching your orgasm. he continues rubbing you for a bit afterwards to ride out your high.
you lay there panting, still wanting more while he rests his hands on your waist. "that feel good baby?" he asks, kissing your forehead lightly and you nod in response.
"want you inside me hee," he smirks at your lewd words.
"you're making me go crazy, c'mere." he carefully pulled you by the edge of the bed and slipped down his sweatpants alone with his boxers.
his cock sprung out, tip red, big, hard, and leaking. he spreads your legs once again and lines himself up to your entrance before pulling back a bit.
"wait i need a condom-" he impatiently looks around his room, trying to remember where he had kept them but he stops when you interrupt him.
"just fuck me raw hee," his eyes widened, mouth slightly open in awe. he had never had raw sex to be honest. his last relationship didn't last very long and she never let him hit without a condom, so this was revolutionary for him.
"fuck.. you don't even know what you do to me yn," he says as he lines himself up once again. he slowly pushed himself into you in one motion, feeling your tight walls.
"oh my god you're so big i-"
"you okay?" he was concerned if you were hurting and you nod immediately to reassure him.
after you adjusted to his size you needed him to move asap.
"feel so full, please fuck me hee,"
hearing you call his name like that turned him on so much. he grabs onto both sides of your waist to hold you in place and started thrusting himself into you relentlessly.
"o-oh fuck!" you squeal and grab onto the sheets, not expecting him to go so fast right away.
"feel so good baby," "fuck this pussy's made for me," he was groaning and rambling as he fucked you dumb.
he was fucking so deep into you and you felt every inch of him hit your walls. the sound of your skin slapping against each other mixed with your moans filled the room.
he wraps his hands under your thighs, going even deeper and you moan loudly again when he repeatedly hits that one spot.
"mm, you like that baby? gonna cum on my dick this time?" his hips moved faster while he leaned in closer to leave wet kisses all over your chest.
"f-fuck i'm close h-hee," you moan. "d-dont stop," you add as you reached your climax again, digging your nails into his back.
he slows down his thrusts, "you feel so good cumming on my cock like that, my perfect girl."
"think you can handle more of me?" he pants, his hands trailing down your body which was still shaking from overstimulation. it had been a while since you had an orgasm, let alone two, however you didn't mind letting him fuck you more since he hadn't finished yet.
"i want you to keep fucking me hee," you said as you pulled him in for a kiss. he slips his tongue in almost immediately, passionately making out with you briefly before pulling back.
"turn around for me," he demands and you obey, slowly flipping your body. he pulls you up a bit and pushes your back lightly, perfectly arching you for him.
he felt his cock throbbing again at the sight of your ass up and face down for him, pussy swollen from making you cum once already.
he bit his lip, "fuckin' beauitful yn," before grabbing your ass and sinking it down on himself.
"h-holy fuck-" you moan at this new angle which hit spots you didn't even know he could hit. his hands were gripped tight on your waist, as if he never wanted to let go.
he pounded into you hard and fast, watching himself slide in and out of you.
"s-shit.. taking me so well baby," "so fucking good for me," his moans were getting more erratic and you could tell he was close. at this point, you felt another orgasm coming.
his thrusts started becoming inconsistent but his pace fastened, chasing his release.
"i-i'm close hee!" you scream.
your body started shaking when your third orgasm hit, your pussy clenching around heeseung's throbbing cock.
"fuck- gonna cum in this perfect pussy," he says as he finally spills his cum inside you.
"god- fuckkk take all of it baby," he groaned loudly and pushed one last time before keeping himself inside for a couple of seconds, releasing every drop inside of you.
you lay there, breathless and shaking the from three orgasms he just gave you. he finally pulls out and watches his warm cum slowly drip out of you.
"holy shit.." he bit his bottom lip before taking his cock again and rubbed it against your pussy with his cum on it.
you whine from the sudden feeling, and then he stands up and goes to the bathroom for a minute without saying anything. your body calms down and he returns with a warm wet cloth.
he cleans you up carefully before cleaning himself too. he lays down beside you after, covering both of you with his comforter.
"you don't know how long i've wanted to do this baby," he suddenly says, turning to you and resting his arm on your waist.
"do what? fuck your best friend's little sister?" you joke.
"yn," he says immediately, pouting.
"okay okay sorry," you giggle.
"tease me like this again and i'll fuck you even with jake around next time."
🧛🏻♀️ a/n: making my debut on here with a brother's bsf trope fic (w/ heeseung ofc) i'm still kinda new to tumblr so bare with me if i did anything incorrectly.. anyway, i hope you guys enjoyed this fic !! <3
© vampheli 2025. all rights reserved.