WARNINGS: NSFW🔞, brocest, !ncest, somnophilia, dub con, non con, breeding, exhibitionism (im envisioning satoru in his mid to late twenties and reader in her early twenties but they can be any adult age you choose) ~ just a drabble~
nerdy big brother satoru is invisible to everyone but his little sister who loves him just a bit too much.
satoru’s kind of smelly, like sweat and must, because he only showers once a month since ‘showering once a day is a scam created by shampoo companies.’ his nose is always runny, and he simply wipes it on his shirt whenever it gets annoying, adding to the collection of food and snot stains on his sleeve. his glasses are pushed up as high as they can go on his face, hiding his features, he never did get his acne under control, and he’s blunt and borderline rude without even realizing it. his hair is a mess, but not in the charming, careless way. he pairs socks with crocs that are a horrendous vomit color because, apparently, ‘comfort’ equals efficiency. when he’s not writing some paper for his physics class, he spends his free time glued to some dumb video game with his online friends that are just as nasty and weird as he is. the only reason his clothes get washed is because he lives at home and his mother does it, picking up his dirty clothes off of the floor for him. the only time satoru interacts with girls is when they make dating him an insult to eachother.
but then there’s you. his little sister who idolizes him, who hangs out in his room because you seem to love his ‘scent.’ you watch him for hours, engrossed in some obscure game or reading up on a random topic with an intensity that makes everything else fade into the background.
he always uses the money he’s earned from being one of the top players in his game to walk you to the ice cream shop, buying you whatever you want. as you enjoy your ice cream, you listen to him passionately ramble about physics or his game, though it can be hard to keep up, since he talks faster than the speed of light when he’s excited. he’s so intelligent that your entire family jokes that he might have been switched at birth.
he always makes sure you have more food on your plate than he does when your mom makes dinner, even though you never finish the huge portion he gives you—he ends up eating it anyway. you sleep in his bed every other night, and he never complains. he just groggily pulls back the blanket and silently invites you in when you stand at his door. you don’t even have to ask him to wrap his arms around you anymore. you feel lucky to be one of the few who gets to see him without his glasses at the end of the day, showcasing his beautiful blue eyes, delicate white lashes, and perfectly coordinated features.
when your big brother complains to you that he’ll die alone and never find a girlfriend after having one particularly rough game match, you can’t help but feel bad for him. he accidentally gets carried away and blurts out that he’s tired of using his own hand to jerk off and he apologizes immediately, pleading with you not to tell your parents. your poor big brother doesn’t even know what he’s doing wrong or how he could possibly understand why girls avoid him.
you’ve seen how your friend who recently entered a relationship spends all her time with her boyfriend, constantly talking about him, and even having him move out of his parents house to move in with her.
you never imagined a world without your big brother. he promised to always be in your life and you can’t fathom otherwise, so when you ask to sleep in his bed again, wearing one of his oversized t-shirts and holding your pillow close, he doesn’t hesitate to make room and let you crawl in. you cuddle into him a little closer than usual but doesn’t mind; in fact, he finds it endearing, the way you push into him, your leg resting over his hip, and your breath warm against his neck. growing up, you were always by his side, hiding behind him, latched to his side. he’s glad you haven’t outgrown that closeness, and he holds you a little tighter too. even when you sniff at his neck and chest like you’re an animal trying to get a scent profile. he just lets out a relaxed breath and nudges his head against yours until you fall asleep.
when his loud, open-mouthed snores let you know he’s fallen asleep, you quietly wiggle out of his big arms and slip beneath the blanket. you pull down his sweatpants and pokémon underwear in one go and you poke at his dick, speaking little words of encouragement to it until it grows and lengthens. it gets so long that it taps your face, right under your eye!
it doesn’t bother you when his body convulses and he busts into your mouth as soon as you latched onto his lanky, thick tipped cock. although it was slightly difficult for you to swallow due to the sour taste, you’re just pleased to be sure that you can please your big brother the way he yearns for.
though, maybe you got carried away because when you get him hard enough to suck him back into your mouth, he wakes up with a hiss. he peers down to see a large tent in his blanket where your head is and feels a wet suction on his cock. he feels around the bed and his nightstand for his glasses frantically.
when he finally manages to put his glasses on, crookedly, and lifts the blanket to reveal you where his dick should be, his jaw drops in shock.
you stifle a giggle as you push him deeper into your throat, each movement eliciting gasps of disbelief from him. he stutters that he must be dreaming repeatedly, lost in sheer ecstasy. his body tenses comically; legs straight out, muscles rigid, back hunched slightly, ass clenched, and his hands form playful stalling gestures as if caught in a delightful seizure.
he busts for the second time, but it’s the first time he’s awake to witness it. his whimpers are so loud, you’re afraid your parents will wake up.
but then you just keep suckling, not even bobbing anymore but instead keeping him warm while swallowing and sucking on it. you think it’s cute as he repeatedly questions, “why??” confused and unsure of how he’s supposed to feel seeing his little sister’s eyes roll back as he ejaculates into her throat for the third time.
satoru starts whining that it hurts when you try to keep going so you pull back and try to catch your breath as his sensitive, utterly wet cock slaps onto his lower abdomen.
he questions you, asking all sorts of things in a shaky voice, as you slowly crawl up his body to straddle his hips, causing him to cringe in the middle of his question about why you did what you just did.
“do you do this while i sleep, often? where did you learn about ‘fellatio’? don’t you know this is wrong?” your responses to his questions are simple—either that you love him, a shrug, or just that you wanted to.
things took a turn when he told you to go back to your bed. you even started crying, and he had to reassure you, telling you as he takes your hand that, of course he still loves you, how could you think otherwise? he’s just really confused.
he nervously says that dad would kill him if he found out and without saying a word, you lean in and press your lips firmly against his. his eyes widen in shock, completely still, as you begin to softly peck him. his hands instinctively shoot up to push you away, but they pause midair. then, you gently slide your tongue across his lips, and then against his teeth and gums, slowly deepening the kiss. his hands gradually lower away from your shoulders, no longer resisting.
satoru doesn’t know how to kiss. unsure of what to do, he just follows his instincts, letting you take the lead. he doesn’t fully register what’s happening until your tongue pushed past his lips and then, without thinking, he just opens them slightly. he gasps, eyes wide, as you eagerly explore his mouth, your tongue licking into every part of his mouth cavity, like a cat grooming its kitten.
you’re whining and whimpering into his mouth like you’re in pain, even saying that your tummy is so full of his cum while you bring one of his hands to it, and he whines into your mouth with guilt, wishing you didn’t just say that. but fuck, he can’t deny how harmoniously blissful it feels when your tongue rubs against his. the second you feel his poor attempt at copying your sloppy kiss, you reach down and force his cock into you to the hilt until his tip kisses your womb.
after the initial, synchronized, blood-curdling gasp shared between you, satoru’s first words are, “we can’t have sexual intercourse as siblings!” but then you’re taunting him with a breathy “why?” over and over. you start to grind down on him, making his cock smear into every crevice in every wall of your insides in a circular motion.
he’s stuttering and whining, “b-because-!” but you just won’t let him finish his sentence or a coherent thought for that matter because you lift and slam your hips down every time he tries, send8!) a jolt of godlike bliss into him.
his single bed with dragon ball sheets creaks and groans with every desperate buck. his eyes are wide with confusion, yet every now and then, they roll in sheer pleasure. as the mix of moans, sticky squelching, skin slapping, and the creaking of his bed grows louder, he whimpers, “mom and dad!”
you know him so well that he doesn’t even need to explain — you instantly understand what he’s trying to say. you reassure him that they won’t wake up, they’re all the way across the house and dad snores so loud, it never wakes mom up, remember? it’s fine! satoru truly hopes so, because his door is unlocked.
as you began to babble about how much you love him, he stutters that he loves you too at first, but soon his little ‘i lo-love you t-too!’s gave way to slurs and desperate whines. he’s trying to focus on enduring the brunt of your movements, bracing himself as if taking a punch, twitching and spasming with every impact and that tight clench of your walls around him, hoping to survive this overwhelming onslaught.
satoru kept his hands to himself for a while now, hesitant to touch you, despite his length disappearing deep into your gushy insides. but when you begin to , slowly and thoroughly lick his neck repeatedly, while you sloppily humped him, his hands shot to your hips, gripping the skin tightly. it’s as though he’s trying to stop you in the name of morals, but the way he digs his fingers into your hips betrays him—he isn’t using nearly enough force to actually halt you.
after you milked him three times with your throat, he’s thankfully lasting longer than he would have inside of a pussy otherwise. still, having only experienced the sensation of his own hand before tonight, he’s already on the brink of cumming after just ten minutes.
he starts frantically begging you to get off, pleading with you to stop and please please get off but instead, you sink your teeth into his shoulder. with one final, forceful plunge down, you stop moving entirely, locking your hips against his, cock so deep that your outer lips press into the skin where his pubes meet.
it’s like you’re using your hole as a suction tube that’s built with the intention to stimulate a humans cock in all the right ways as to collect semen efficiently. he feels like he’s tied down by metaphorical ropes and forced to cum into the tube with no way of fighting it.
his warnings urge you to reach between your bodies and circle your clit frantically. it doesn’t even take thirty seconds for you to cum because just the thought of him releasing his purest form of love into your heart shaped womb is too precious.
his breathing is erratic, almost alarming, while his eyes flicker and twitch. his toes curl, and his hips jerk up involuntarily one last time as he pleads ‘noo!’ one last time. his mouth hangs open in a way that almost looks comical as his cock jolts, breeding you. if you could somehow see inside your body with an x ray of sorts, you’d witness the way his cock twitches in tandem to the cum traveling through it, only to be drawn in and milked by your pulsing walls, perfectly made to collect it. you feel absolute bliss, as his dna pools within you, bringing you as close as physically possible.
you collapse onto his body, both of you gasping for air. with a shaky hand, he adjusts his crooked glasses, carefully straightening them.
despite everything, satoru softly asks if you’re okay, his tone full of the brotherly concern you love so much. you hum happily in response, your body reacting as your pussy clenches, making him let out a guttural wheeze, as though he’d been punched in the stomach. you both stay like that for a long time, and when you ask him to, satoru gently rubs your back, just like he does when you can’t sleep, while you rest against him, his cock still warm inside your body.
he listens carefully, straining to hear any sign that your parents are awake as you lie together in the afterglow. thankfully, he hears nothing. when you start showering sweet kisses along his neck and up to his jaw, he feels a flutter in his stomach, and his cock jerks. but he pulls his head away slightly and gently grabs your shoulders to pull you away, looking you in the eye. you break free from his grasp and continue kissing him all over his face, even as he tells you this is wrong and it can never happen again.
but satoru can tell himself whatever he wants because twenty minutes and an energy drink from his mini fridge later, he’s pounding you into his bed like his life depends on it. you cry out, eyes permanently rolled to the back of your skull as he’s forcing you to stay deep down in a mating press. he’s pushing you down with more force than he realizes, the stretch painful as he’s unaware of how much weight he’s placing on you. you can barely breathe, but you don’t mind. you know it’s because he’s inexperienced, too lost in the ecstasy between your legs to pay attention to anything else.
satoru even starts crying pathetically in utter guilt as he ruts into you sloppily and erratically hard because he’s not used to this hip motion or exercise in general. he’s whining drawn out and pathetic that he’s so sorry, over and over again, babbles that he’s just not used to this and can’t stop. to comfort him, you grip his tear-streaked cheeks and pull him close, encouraging him to drop his full weight onto you into a deep hug, above and below. you kiss him deeply, exchanging breaths and saliva, offering reassurance in the midst of his turmoil that it’s okay i love you.
many positions and rounds later, pillows and blankets are everywhere but the bed and he’s basically just sloshing his own cum back into you. the only evidence of cum around the room is between your legs because big brother satoru can’t possibly find the willpower to pull out now after you showed him how intimate a creampie is.
by the end of the night, you’re both so exhausted that you end up sleeping through the entire next day. your parents find it endearing how close you two still are, thinking it’s cute that you spent all night playing video games together, especially since satoru has no friends. however, when they make a comment about you guys being too loud, satoru nearly breaks down crying, about to confess everything. thankfully, under the table, you manage to grab his cock through his pants just in time, freezing him in place as you quickly make an excuse to your parents and apologize for the noise.
satoru likes to insist it was just a one-time thing whenever the topic comes up in conversation, especially when you tease him about it. but no matter how much he tells himself that, it just keeps happening—again and again.
the second time it happens, you rub him through his sweatpants at dinner without even looking at him while you tell your parents about an upcoming project for one of your lectures. he tried to make you stop but he busts in his pants. he even got mad at you for a few hours after, ignoring you with a hard expression until you surprised him with his favorite mochi and said you’re sorry. (you’re not.)
the third time, you claim that you want to take a bath with him like old times and your parents just love how much closer you guys are lately! satoru even believed your innocent act as you sat with your back to his chest in the water, until you lodged your brother into your pussy. when he started reprimanding you, you explained to him that cock warming isn’t fucking and sat there for thirty minutes. satoru ended up being the one to grow impatient. he wrapped one arm around your chest and shoulders, one around your lower hips, and humped up into you like a rabbit, making a watery mess on the floor. he doesn’t much care for cock warming.
the fourth time, satoru gets a job to buy a car just so he can drive you two out to an anime convention on a little siblings trip. you ended up fucking through the whole weekend without ever even leaving the hotel room. nerdy satoru even initiated some of it: telling you not to sleep in the extra bed, giving a little peck goodnight with the claim that a small peck is healthy between family (not like your other kisses at all), cuddling you into him like you’re his own personal stuffed animal, telling you how much he enjoys spending time with you, rubbing his hands up and down your back affectionately. it’s not long until his hands venture down to your ass and then before you know it, he’s thrusting into you as he holds your head so it doesn’t bang into the head board.
the fifth time, you sneak under his desk as he wrote a physics paper and you drank milk until you grew sleepy and passed out on his thigh as his cock twitched and kissed your cheek in appreciation. he wrote the word ‘the’ in the span of an hour.
the sixth time, you were doing a family movie night, and someone had to make popcorn so you and satoru hopped up to make it, since that’s a two man job, according to you. stovetop popcorn is just so much better than the easy microwave one your parents urged you to do. the second you turn on the stove, you called out that you couldn’t even hear the movie and grabbed the remote from the counter to turn it all the way up as satoru kissed your neck. your mouths crashed together the second you put the remote down and it doesn’t take long for him push you to lean over the counter and slowly, slowly slide in and out of you as to not make a lot of noise while your parents were mere feet away, happily unaware while the popcorn is popping. just in time, the popcorn timer went off as you came.
the seventh time, you were at some college party and you fed whispers into his ear in the corner of the room as you -not so subtly- pawed at his growing bulge. detailed coos of how you wanted him to fuck and lick and finger you as his eyes swirled in a spiral. he nervously fingered you, terribly with inexperience, in the bathroom before you got frustrated and shoved his face into your slit. it was so nice to make out and grope him in public where no one knows you’re related<3
satoru doesn’t mind not having a girlfriend anymore.
——
BAM! BROCEST
expect a lot of brother satoru from me in the future















