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isek4i · 2 months ago

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⠀⠀⠀⠀⠀⠀⠀SOAKED AND SPENT, ⠀⠀⠀S. SANEMI ⠀⠀⠀⠀⠀⠀⠀⠀⤿⠀ ft. ⠀stepbrother!sanemi

sum. what begins as a routine gesture of care from his sister, sanemi decided to unwind from the pent-up stress of the weeklong mission in a way he knew best.

content & warnings. stepbrother x stepsister pairing. fem reader. dom!sanemi. forbidden relationship. sexual tension. teasing. bathtub sex / water sex?. rough sex. controlling and impatient themes. nipple play. pet names. reader calls nemi 'onii-chan'. groping. unprotected piv sex. tension & smut. reader is legal. wc. 4.3k author notes. incest is gross unless sexy slayer nemi is your older brother :)

“you’ve had a long day,” came your soft whisper behind him, breaking the stillness of the evening.

sanemi sat perched on the edge of the engawa, his gaze locked on the horizon as the sun dipped low. a golden hue casted over his tense frame, the sight something you couldn’t look away from. the silence was heavy as he mentally sifted through the remains of his exhausting mission.

“i’ve already prepared you a bath,” you added gently, your voice hesitant, as though unsure whether to disrupt his thoughts. “when you’re ready.”

sanemi’s head tilted slightly, his eyes still fixed on the horizon. the muscles in his jaw twitched, his silence stretching thin as the air between you thickened. a long, controlled exhale escaped his lips before he finally turned to look at you.

his gaze, sharp and unreadable, landed on your form. at his full height, sanemi’s presence was always imposing, but seated as he was, he looked almost vulnerable. almost. until his eyes swept over you in that slow, calculated way that made your skin prickle with awareness.

his lips twitched, a flicker of something that was neither a smirk nor a smile. “you’re going to help me, right?”

the words hit you harder than they should have. “help. . ?” your voice faltered, your breath catching in your throat as the weight of his question settled over you.

sanemi’s sharp gaze narrowed slightly, his tone low and steady as though daring you to challenge him. “yes. help. like you always do. get in with me to wash my back, my hair.” the bluntness of his words was cutting, but the way he leaned forward, just slightly, softened the edge. sanemi’s brow raised, his expression expectant.

“r-right, of course.” you stammered, composure slipping as heat crept up your neck and into your cheeks. you turned your eyes back to the fading sunset, hoping to steady the erratic beat of your heart.

but sanemi wasn’t just watching you — he was studying you.

the way his gaze lingered too long, the way his silence held more weight than his words. the air grew heavier as his presence seemed to fill the space between you. It wasn’t new, this routine of tending to him after a mission, but tonight there was an intensity to him that hadn’t been there before.

the tension in his shoulders was palpable, his tightly coiled energy barely concealed beneath his outward composure. like a predator biding its time, he was unnervingly still, his gaze searing into you as though waiting for you to make a move.

then, with deliberate slowness, sanemi reached up.

his calloused fingers brushed a stray strand of hair away from your face, lingering for a moment longer than necessary as his fingertips grazed your cheek. the roughness of his hand against your warm skin sent a shiver down your spine. his eyes softened just barely, a flicker of something intimate that made your pulse race, even as his voice stayed rough and commanding. “come on,” sanemi said, his tone almost a growl. “let’s go.”

the walk to the bathing quarters felt unbearably long, each step echoing in the silence between you. you could feel his presence behind you, his gaze heavy on your back, unrelenting. every brush of his hand, every moment his breath seemed just a little too close and left your heart pounding harder. the space between might as well have been nonexistent, and yet you both walked as if tethered by an invisible string, pulled tighter with every step.

by the time you reached the shoji door, the silence was deafening, the tension a living thing between you. sanemi wordlessly starts to undo the fastenings of his uniform without wasting much time.

“strip.” he orders as he starts to undress himself.

“huh. . ?” you thought you misheard, slightly wide eyes turning to him.

sanemi rolls his eyes again when he sees your reaction to his command. he’s just as stoic as usual as he continues to undress, not fazed in the slightest. if anything, he seems slightly impatient as he continues to remove his clothes.

he shoots you an unamused look. “i said strip. i’ve had a long week.”

your jaw dropped softly, face and ears warm. you averted your gaze just when he tossed off his haori and uniform shirt. as sanemi made a work of his hakama, you slowly and hesitantly started undoing your obi slowly, the warm and steamy air of the bathroom making a shiver run down your spine.

gaze lowered, you discarded your clothing one-by-one on the tatami mat until you were left in just your thin white undercloth. pulling that over your head, you let the fabric drop. now left in nothing but a short loincloth.

sanemi watches you as your clothes were casted off at his command, his gaze intense and unwavering. his jaw clenches slightly as his eyes scan over you up and down, lingering on the curve of your breasts and nipples gradually hardening from the air. the view of you like this, almost completely naked, was doing. . . things to him ― despite not being a stranger to the scene. sanemi can’t tell whether it’s a good thing or a bad thing though.

“you’re taking your sweet time. . .” he mutters as he finally steps out of his hakama, eyes never leaving your form.

your face was still hot as you tugged off the cloth, letting it drop. you stood completely naked and vulnerable in the small space, a shiver running down your spine while sanemi briskly discarded his own clothes. you could feel the prickle of his piercing eyes on you despite not looking directly at him, and the scrutiny made you fidget.

the sight of you, standing there fidgeting with your fingers, your gaze averted and cheeks red from embarrassment all made hot blood rush down to his cock. sanemi almost felt his breath catch in his throat, his gaze never once leaving you and roving over every exposed piece of skin, taking you in as if he couldn’t get enough of the view.

sanemi kicks his clothes aside before stepping closer to you, the air around you suddenly feeling hotter, his eyes slowly making their way up your body, from your breasts to your face. “get in the bath,” he mumbled, voice low and impatient.

you nodded softly and turned to walk into the bath, steps silent on the tatami mat. just before stepping into the warm water, you bent over softly to take off the socks on your feet.

yet as you turn around to the bath, walking silently, it gives sanemi a perfect view of your behind. a guttural growl suddenly leaves him, his hands reaching out almost of their own accord to grip your hips, yanking you backwards against him.

sanemi presses himself against you, his entire body practically burning with desire now that you’re so close to him. “you keep teasing me like that and neither of us will be getting in that bath anytime soon.”

“onii-chan. . !” the honorific left your lips in a gasp from surprise at the motion, stumbling back and clutching the rim of the tub for stability. “i-i wasn’t teasing. . .”

the sound of that gasp-moan leaving you, the way your body trembles when you feel his hips press against you makes his hands tighten their grip on your skin, his eyes narrowing and darkening in desire. “you knew exactly what you were doing,” sanemi growled, voice low and rough in your ear, his chest flushed against your back. “walking across the room like that, bending over to take your socks off like that. you know what that does to me.”

“i-i’m sorry!” your voice was soft and slightly breathless, fingers gripping the edge while you were pinned in place. you felt every inch of him ― from the hard muscles of his hips, to the curved length of his cock, and the moist tip brushing right against your clit. knees feeling like jelly, you stayed arched and still. “i-i didn’t mean to. . . i was just getting into the water.”

“then why did you bend over instead of kneeling down to take off your socks?” sanemi growls, his rough hands shifting from your hips to run up your waist slowly, his warm touch tracing your skin, the sound of his voice low and ragged in your ear. “are you trying to provoke me?”

his voice grows huskier, almost dangerously rough as his hips press you harder against the rim of the tub, feeling the tip of his cock prod your slit. “are you trying to drive me crazy?”

“i-i was just. . .” you stuttered, unable to think straight with the way your knees almost buckled, walls clenching around nothing. “i-i’m sorry. . . c-can we get in the water now. . .? i. . .”

you can practically hear the smirk in sanemi’s voice as he hears your attempt to respond, how your voice stutters and quivers, can almost see the expressions you’re making from having his body pressed flush against yours ― from his hips grinding against yours.

“getting impatient now, are we?” sanemi mocks, his hands roaming up the sides of your body with more confidence, his palms coming to grope your full breasts to emphasize his words, tweaking your nipples almost teasingly. “can’t wait to get in the water with me?”

“s-sanemi,” your eyes squeezed shut, his touch making you borderline delirious. your knuckles turned white from how hard you clutched the edge of the tub for your sanity. and to prevent yourself from bucking back into his cock. “yes, i. . . i want to get in with you.”

the sound of your whimper, the arch of your back all cause his already racing heart to beat even faster, the need to touch you, the want to keep you making his whole body feel like it’s burning.

“then get in the water,” he breathes in your ear, his tone rougher now, his rough hands on your breasts squeezing softly.

“a-as long as you,” your voice was soft and shaky, eyes fluttering shut at the motion that sent tingles down your spine and between your legs. “get in me ― i mean, get in with me. . !”

a guttural, low growl suddenly leaves sanemi at your slip of tongue, a rush of desire and need coursing through him, the sound of your trembling voice sending a shock of fire through him. “of course I’m getting in with you.” he practically snarled, his voice thick and rough as he squeezed your breasts harder.

sanemi suddenly lets go of you to turn and get in the bathtub, the water making ripples as he does so, before he looks up at you. “get in. now.”

you stepped into the tub after him, fingers softly grasping his shoulders for stability since you didn’t trust yourself. his arms immediately wound around your waist while you both sunk into the water, straddling him softly.

you were almost panting and sanemi hadn’t even started yet.

the feel of your fingers on his shoulders, the way you press against his body as you both sink into the water, the fact you’re straddling him now ― sanemi moans at the feeling, hands coming to settle on your hips instinctually, a muscle twitching in his cheek as he looks up at you. he could feel the soft petals of your pussy wrap deliciously around the length of his cock, from the way your hips were pressed together.

“you’re so needy,” he grumbled, the words an attempt at mocking, but it’s obvious he’s struggling to remain calm now, his breath ragged.

it was hard for you to keep any semblance of control, especially from the way the heat on your cheeks wouldn’t dissipate. yet his words made your lips twitched upwards slightly, nose bumping against his softly. “hardly. . .”

“oh, really?” sanemi murmured, his eyes narrowing slightly as he looks up at you, the affectionate motion both adorable and sexy at the same time.

his hands gripped your hips harder, pulling you down so that the head of his cock would trace your clit to the rosy bud of your asshole, grinding up against you to make his point. a hiss is heard as he does that, his breath labored. “you’re pressing your body up against me like this, and you’re saying you’re not needy?”

“you’re the one guiding my hips.” your voice a breathless giggle, the sound making him let out a low, guttural growl. his hands pulled you down even more firmly on his lap, his hips instinctively bucking up against you.

“yeah, cause you’re too slow,” sanemi scoffed, hands roaming further down your body to grab the firm globes of your ass now, hands strong. “come closer.” his voice is low, sounding like an order.

you didn’t think twice before your arms tightened around his neck, nose brushing against his with every roll of his hips, and your bodies were pressed together. every breathless gasp of yours, including the whimpers under your breath, drove sanemi crazy.

there was something about the tease and the repetitive rub of his cock on your pussy that made him feral, how he was barely a buck away from taking you. “don’t stop. just like that.” his breaths were hot and ragged.

“onii-chan. . .” your voice was a soft and shaky whine, honorific dropping from your lips in a daze. you kept rolling your hips slowly, eyes fluttering shut. a shiver ran down your spine every time his fat cock rubbed against your sensitive and swollen clit.

the water in the tub sloshed with every jolt. sanemi’s nails dug into the smooth flesh of your ass as he guided your movements, almost leaving marks there. “you’re so perfect, baby,” he panted in between breaths, tongue suddenly coming out to flick the skin at the base of your neck, the need to taste you taking over him. “you’re killing me.”

“just. . .” every grunt and low rasp of his voice only seemed to make you more desperate, walls twitching around nothing as the emptiness in your womb became more apparent. your hips squirmed with intent, trying to press the fat tip of his cock against your slit enough for you to sink down. “stop teasing. . . please.”

sanemi’s breath is ragged, the feel of your hips pressing down nearly destroying his self-control, his eyes narrowed hotly as he stares up at you. “push my cock in if you want it so bad,” he finally growls, his voice nearly guttural now. “do it.”

you didn’t have to be told twice before your fingers dipped into the water to shakily grasp the length of his hard cock, pumping it a few times. your thumb swiped across the slit on his tip before guiding it to your quivering slit, and sinking down slowly. “god, yes.”

both of you groaned in sync, the water making it easier for his fat cock to slide in. the thick length was usually hard to take in one go, but his absence combined with your need to help him destress made your cunt more eager.

sanemi’s breath became labored as a near-animalistic noise rips itself from his throat. “fuuuck,” he growls, the curse sounding choked as he tries and fails to suppress the wave of pleasure from his cock finally being wrapped around your moist walls. “all the way in? in one go? fuck, little girl.”

“i-i just. . . ah, missed you.” you couldn’t even think straight from being stuffed so full. sanemi guided you against the edge of the tub while your back curved over, his rough palms hurriedly pushing your thighs over his shoulders. you were practically folded in half over the rim, while his rough fingers held your ankles in place. “o-oh, my. . .”

sanemi panted, his breaths hurried, body burning with need. it was hard for him to be any gentler now, as he positioned you, his cock still buried deep in. a ragged breath left him at the sight of you bent over. “let me. . .” he whispered, voice hoarse with desire. “let me. . . try something first. . .”

“a-anything you want. . .” fingers softly gripped the edge of the tub, your head dipped back and eyes fluttered shut. sanemi groaned huskily at your response, your body shuddering and quivering pleasingly. he loved the effect he had on you.

the water sloshes around you both from his movements ― all of it causing sanemi to ache for you. “i’m gonna go a little deeper now,” he panted, his cock slowly dragging out of your cunt as you felt every single vein and curve rub your walls, his voice hoarse. “hang on to me for a bit.”

“o-okay. . .” you cried out quietly, delirious from the sensations. every touch, every breath, his cock; it was all too much. he was so big and the way he pressed down on you left you breathless. your mind was dazed but your body was hyperfocused on the way his fat cock rocked back into you inch-by-inch.

sanemi swallowed thickly, his body burning with need, before speaking. “i’m a little worried. . . that i might break you if i go any rougher,” he mumbled, his body shuddering as he thrusted in your tight cunt slowly. “you’re so small…”

“‘m not s-small. . . you’re just too, ngh, big.” your shaky fingers gripped his scarred but firm biceps and you bit your lip softly to stop any loud noises. sanemi’s large frame took up most of the space in the tub, each muscle in his body coiled and flexed with his movements, keeping you pinned against the tub and rocking slowly. “i’ll be fine. . . i want you to ― ah! ― use me.”

your tiny fingers gripping his beefy biceps, the way your voice trembled as you begged for him, all of it nearly made him snap. a guttural, desperate noise leaves his throat as he practically snarls “are you sure, little girl?”

he suddenly gripped the backs of your thighs even tighter, his nails digging into your skin in this possessive way. “once i go rougher, i won’t be able to stop. i don’t know if i’ll be able to hold back.”

“good.” you exhaled shakily, water sloshing softly around you both. “please do it. . .”

the sound of that word from your lips was dangerous, nearly pushing him over the edge from the need he felt. your thighs quivering, your back arched over the edge of the tub ― all of it was too much for sanemi to handle. “you asked for it, baby,” he almost growled, his body shuddering as he shifted against you, still gripping you tight. “just don’t pass out like last time, alright?”

“i’ll try not to. . . ah. . !” you couldn’t complete your sentence before his hips started, a soft scream leaving your lips. you instinctively clenched around his cock, walls wringing him tight like a vice. your words died on your lips, only able to muster incoherent whines and moans between cries.

“i don’t think i care, actually.” sanemi mutters, his tone dark but breathless. he let out a low growl, the sound ragged as he started thrusting his cock in and out of your tight cunt, the sound of the water sloshing softly around you both filling the air. his hips moved with ease from the lubrication of the water, the tip of his cock kissing the entrance of your womb.

“just keep your sweet voice like that. let me hear you,” he breathed, the words a low grunt in your ear. sanemi was utterly pussy-whipped. “moan my name. call for me.”

“y-you don’t care that i pass out or not. . ?” your voice shook breathlessly and your body jolted with every thrust, trembling hands gripping his biceps. sanemi grips you tighter, the water sloshing and rocking against the sides of the tub.

“not if i get to do this,” he panted, one hand gripping the back of your thigh roughly, the other gripping your waist to hold you in place against the tub. “that’s all i care about right now,” he grumbles, eyes focused and burning intently on you. “keep making pretty noises,” he mumbled. “tell me how much you feel.”

your legs felt like jelly, mind dazed and shaky fingers latching on to his shoulders, almost leaving scratch marks. your voice was a soft mewl from the raw pleasure. “onii-chan. . ! yes, it feels so good, i can’t take it. . . ah!”

the feel of your nails scratching him, the sound of your voice hiccupping shakily in his ear, all of it just added fuel to the fire in his core. “you’re so cute,” sanemi grunted, his voice huskier now, cock thrusting faster and rougher in your cunt. “say my name.”

“sanemi. . .” you moaned in his ear, unable to keep your eyes open. your fingers gripped his shoulders and nape, desperate to hold something for stability, nails leaving angry red marks on his scarred skin. “i-i love it. . . love your cock so much. . .”

“fuck, good girl.” he growled, his voice sounding increasingly rushed and breathless now, his nails digging into your skin from how tightly he was holding you, thrusting at an animalistic pace. sanemi was ruthless. “can’t live without your big brother’s cock, huh? say you love me. tell your onii-chan how much you love him.”

“onii-chan. . .” you babbled mindlessly, unable to think or do anything besides feel each rough drag of his hard cock, the curve of his length hitting all the right spots inside you. “i love you. . . i love you so much!”

your lips pressed against his neck softly, trying to trail kisses down his neck, but every thrust of his hips made you dizzy and lightheaded. “a-ah. . ! there ― !”

sanemi let out a guttural sound of satisfaction at your words, your soft, shaky voice telling him what he always wanted to hear, your lips against his skin making his heart pound faster.

“keep talking,” he panted out. “just like that. please,” he breathed, his body shuddering against yours as his hips rocked against you, cock angled to thrust right into that sweet sport repeatedly, your toes curling over his shoulders. “your little pussy’s gripping me so tight, shit.”

“oh, god. . . oh my god.” your back arched, clinging to him for dear life as you spasmed softly from the direct hits of his springing hips. you couldn’t even think anymore. “i-i can’t feel my legs anymore. . . ah ― it feels so good, i’m gonna cum ― !”

sanemi growled in response to your words, a shudder running through his body as you started shaking and trembling against him, the feel of your body clinging to him driving him insane.

“fuck, i’m close too.” he breathed, though his voice was rough and ragged. “just a little more. . . god, that cunt ― i need to hear you moan just one more time,” sanemi shivered while still rolling his hips bruisingly and unrelentingly. “just a little more for me, baby. can you do that for your onii-chan?”

“yes,” your eyes were teary and dazed. body tensing and arching, his cock managed to dumb you down and babble his name like a chant. “i-i can ―”

mid-whimper, you ended up cumming on his cock, his blunt nails digging into your skin as the spasm of your walls caused him to cum too. sanemi grunted filthy praises under his breath while he buried his full length in your cunt to the hilt, emptying his balls of a hot and creamy batch of cum deep in your womb.

you could feel the twitch of his cock being milked of its slimy knot, belly almost bulging while you both succumbed to the high. your gummy walls convulsed around his softening length, his once piercing cock that you felt in your stomach now weak and spent as sanemi slumped against you.

his larger figure nearly covered you as he leaned down, his heavy breaths hot and languid on your skin as he slowly came back to his senses. “damn,” he panted, still a bit shaky from it, before a small chuckle escaped him as he looked down at you. “god, i’m gonna need that again.”

“a-again. . ? God, you’re an animal. . .” your voice was slightly croaky from all the screaming as you shivered, hot bath water now cold. your body felt weak and jelly-like from the aftermath, burying your face in his chest between pants. “although i can never say no to you. . .”

sanemi shifted against you, his hands still holding you against him. “we’re not done yet, anyway. i only went once.” his hands slowly started to wander over your body again, one hand slipping upwards to grasp your breast, thumb brushing over your nipple.

you huffed softly but his next words made your face flush, softly smacking his chest. you couldn’t protest much when he carefully put your legs down, before slowly lifting you out of the tub bridal-style. “it hasn’t even been five minutes.”

sanemi smirked, his voice dripping with playful arrogance as he carried you effortlessly. “five minutes is plenty of time for you to recover. . . but not nearly enough to satisfy me.”

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