The Hawaiian sun is a hammer on the private beach, the sky a brutal, cloudless blue.
Izuku digs his toes into the hot sand, watching Katsuki adjust the umbrella over the stroller where Natsuki sleeps, his little chest rising and falling in the shade. Ochako’s text from the spa—a photo of a cucumber slice on her eyelid—sits unanswered on Katsuki’s phone, on their rented lounge chair.
“He’s out,” Katsuki says, his voice a low scrape against the crash of the surf.
Izuku’s fingers find the hem of his loose linen dress. Katsuki’s crimson eyes are on him, a gaze hotter than the sun. He pulls the fabric up and over his head in one smooth motion, letting it fall onto the hot sand. Underneath, the purple and green mermaid-scale bikini is two scraps of string and shimmering fabric: the top barely contains his small chest, the triangle bottoms cut high on his thick thighs, leaving the full curve of his ass bare.
Katsuki’s breath stops. His jaw goes slack, then tightens, a muscle pulsing in his cheek. His gaze drags down Izuku’s freckled body, over the tiny swells of his tits, the dip of his waist, the blatant outline of his pussy through the sheer green fabric. The front of Katsuki’s board shorts tents, the thick outline of his cock unmistakable, already leaking a dark spot onto the fabric. “Fuck,” he rasps, the word swallowed by the surf.
“Like it, Daddy?” Izuku asks, his voice a little unsteady. He turns a slow circle, feeling the ocean air on his exposed skin, the heat of Katsuki’s stare like a brand. People are just down the beach, distant laughs carried on the wind. It doesn’t matter. Nothing matters but the raw hunger on Katsuki’s face.
“You planned this,” Katsuki says, closing the distance between them in two strides. His hand is rough on Izuku’s hip, thumb digging into the bone. “Wore that under your dress all fucking morning. While we had breakfast. While we pushed the stroller.”
“Maybe.” Izuku’s heart isn’t hammering—it’s a slow, heavy thud against his ribs. He can smell the salt on Katsuki’s skin, the sandalwood, the pure male heat of him. His own pussy is already slick, the tiny bikini bottom soaked through. “Wanted you to see.”
Katsuki’s other hand comes up, his calloused fingertips tracing the string at the side of Izuku’s hip. “Anyone could see. Anyone could look at you right now and know exactly what you are.” His voice is a low growl, his cock pressing insistently against Izuku’s thigh. “My fucking slut.”
“Yes, Daddy. Your slut,” Izuku breathes, and it’s not just agreement—it’s a truth that lives in his marrow. He leans into the touch, his head tipping back. The sun is blinding. The baby sleeps ten feet away. He’s never been so exposed, so wanted.
Katsuki’s fingers hook into the side ties of the bikini bottom. One sharp tug and the knot gives. The scrap of fabric falls away, and Izuku is naked from the waist down, the ocean air cool against his wet folds.
Katsuki’s hands leave Izuku’s hips. He takes a step back, his breathing ragged, and walks the few paces to their rented lounge chair. He sits, the canvas creaking under his weight, and his eyes never leave Izuku’s naked form. His fingers hook into the waistband of his board shorts, shoving them down just enough to free his cock. It’s thick and flushed, uncut and already weeping, standing rigid against his stomach. The sun glints off the slick bead at the tip.
“Here. Now,” Katsuki says, his voice a graveled command. He spreads his legs, planting his feet in the sand. “Spread your legs over me. Pussy facing out. Show them what you are while you fuck yourself on it.”
Izuku’s breath hitches. He can see the distant figures down the shore, too close to them. He can hear Natsuki’s soft, sleeping sigh from the stroller. His pussy clenches, empty and aching, a fresh trickle of wetness sliding down his inner thigh. He doesn’t hesitate. He turns his back to Katsuki and steps on the outside of his spread knees.
He reaches back with one hand, fingers spreading his own slick folds apart, presenting himself. The ocean air kisses his exposed hole, making him shiver. He lowers himself, the broad head of Katsuki’s cock nudging against his entrance. Izuku’s inner monologue is a silent scream of yes, of finally, of this is where I belong. He sinks down in one slow, brutal slide.
The stretch is exquisite, a burn that melts into a deep, filling ache. He takes every inch, until his ass is flush against Katsuki’s stomach, until he feels Katsuki’s heavy balls pressed against his pussy. He’s fully impaled, legs spread wide in a vulgar squat, his own pussy stretched wide around the thick cock buried inside him, openly displayed for anyone who might look their way.
“Fuck,” Katsuki groans, his hands coming up to grip Izuku’s hips, his thumbs digging into the dimples at the base of Izuku’s spine. “Look at that. Look at you taking it all. Anyone can see how greedy your little cunt is.”
Izuku starts to move, a shallow, rocking grind that makes them both gasp. The wet, filthy sound of his body taking Katsuki’s cock is loud in the space between the crashing waves. He can feel every ridge, every pulse. “Daddy,” he whimpers, his head falling back against Katsuki’s shoulder.
“Eyes open,” Katsuki snarls into his ear, one hand sliding around to splay possessively over Izuku’s lower belly, as if he can feel himself through the flesh. “Look at the water. Look at the people. They could be watching. They could be seeing my babysitter’s used-up pussy getting wrecked on his daddy’s cock.”
Izuku forces his eyes open, his vision blurring with pleasure. The Pacific is a vast, blue expanse. A family is playing with a beach ball maybe a hundred yards down. His cheeks flame, but his cunt clenches tighter, gushing around Katsuki’s shaft. He rises up, almost letting the head pop free, then slams back down, taking him deep again. A broken moan tears from his throat.
“That’s it. Ride it. Give them a show,” Katsuki grunts, his own hips beginning to piston upward, meeting Izuku’s desperate drops. The lounge chair jerks in the sand with their rhythm. Sweat slicks Izuku’s back where it presses against Katsuki’s chest. The hand on his belly presses down, holding him in place for a deeper, grinding thrust. “You’re so fucking wet. Dripping all over me. My little beach slut.”
A couple appears coming towards them, strolling hand-in-hand along the tide line. They’re closer than the family with the beach ball, close enough that Izuku can see the woman’s sundress, the man’s baseball cap. Their casual walk slows. Stops. The man’s head tilts. The woman’s hand flies to her mouth.
Katsuki’s hips stall beneath him, his cock a hot, rigid brand buried to the hilt. His grip on Izuku’s hip tightens, a silent command to hold still. “Look,” he rasps, his breath hot and ragged against Izuku’s ear. “Two o’clock. They see you. They see my cock splitting this pretty pussy open.”
Izuku’s whole body flushes, a wave of heat that has nothing to do with the sun. He can feel their stares like physical touches, crawling over his spread thighs, his ass planted in Katsuki’s lap, the obscene joining of their bodies. His pussy pulses, a fresh gush of wetness soaking Katsuki’s shaft. He’s horrified. He’s so turned on he can’t breathe.
“They’re staring at your filthy cunt, baby boy,” Katsuki growls, his voice low and vicious with pleasure. “Watching it suck me in. Look at her face. She’s scandalized. He’s getting hard watching you.”
Katsuki’s free hand comes up, fingers tangling in the strings of Izuku’s bikini top. One sharp yank and the knot gives. The shimmering fabric falls away, and Izuku’s small tits are bare to the salt air, his puffy, dark nipples already hard and aching. The couple is frozen, twenty yards away, unmistakably watching now.
“Daddy,” Izuku whimpers, the word a broken thing.
“They can see your tits bounce,” Katsuki says, and he starts moving again, a shallow, grinding thrust that makes Izuku’s whole body jerk. His nipples bounce with the motion, a lewd display. “They can see how fucking wet you are. Show them. Move.”
Izuku obeys, a choked sob escaping his lips as he rises and sinks back down, the slide wet and loud. His eyes are locked on the couple. The woman is tugging the man’s arm, but he’s not moving. He’s just staring, his eyes wide, fixed between Izuku’s legs.
“He likes it,” Katsuki grunts, his own thrusts turning harder, deeper, jostling Izuku violently. “He’s imagining it’s his cock you’re riding. That your tight little hole is milking him instead of me. But it’s not. It’s mine. Say it.”
“Yours,” Izuku gasps, his vision swimming. The humiliation is a live wire in his gut, fused inseparably with a pleasure so sharp it feels like dying. “Your cunt, Daddy. Your slut.”
Katsuki’s hips slam upward, brutal and ruthless, driving his cock so deep Izuku sees white behind his eyelids. The man in the couple isn’t moving away. He’s standing there, frozen, one hand at his side, the other adjusting the obvious, thick bulge in his own shorts. Izuku’s pussy clenches, a fresh flood of wetness easing the violent slide. He rides down harder, bouncing on Katsuki’s lap, making his small, bare tits bounce obscenely.
“He’s hard for you, baby boy,” Katsuki snarls into his ear, his hands like vises on Izuku’s hips, controlling the punishing rhythm. “Look at him. He’s imagining this tight little hole wrapped around his dick instead.”
Izuku moans, high and broken. He reaches down with one trembling hand, fingers spreading his own soaked folds wider, presenting his stretched, glistening entrance to the stranger’s hungry stare. The humiliation burns like a brand, but it’s drowned out by the deeper, darker thrill of being watched, of being wanted even like this.
The man takes a step closer. His girlfriend says something sharp, tugging his arm, but he shakes her off, his eyes glued to the place where Izuku’s body swallows Katsuki’s cock.
“That’s it,” Katsuki grunts, his own breath coming in ragged gusts. He suddenly shifts his grip, his powerful arms hooking under Izuku’s thighs, lifting him and pulling him back against his chest in a brutal full nelson hold. Izuku is completely immobilized, legs spread wide in the air, his back arched, his pussy utterly exposed and impaled. Katsuki fucks up into him, short, savage pistons of his hips that jolt Izuku’s whole body. “Let him see how I wreck what’s mine.”
The man is close enough now that Izuku can see the sweat on his temple, the parted lips, the dumbstruck hunger on his face. He’s maybe fifteen feet away.
“How’s the show?” Katsuki calls out, his voice rough but clear over the surf. He doesn’t stop moving, his balls slapping wetly against Izuku’s ass with every drive.
The man—Yo Shindo, his mind supplies uselessly—gulps. His Adam’s apple bobs. “Fucking… hot,” he manages, his voice strangled. “You two are fucking hot.”
Katsuki lets out a dark, approving laugh. The sound vibrates through Izuku’s back. “Yeah? You like watching my boy take it? See how wet he gets for an audience?” He punctuates the question with a deeper, grinding thrust that makes Izuku cry out, a gush of fluid soaking both their thighs.
Izuku’s mind fractures. The sun is too bright. The salt air stings his lungs. His nipples are hard, aching peaks. The stranger’s eyes are on his cunt, on the place where he’s split open, and it feels like praise, like absolution, like the most profound kind of nakedness. He’s not a secret here. He’s a spectacle. Katsuki’s spectacle.
“He’s gonna cum,” Katsuki announces, as if commenting on the weather. His thrusts become erratic, losing rhythm for pure, driving force. “Gonna make this slut squirt all over my cock. You wanna see that?”
Yo Shindo nods, once, a jerky movement. He doesn’t speak.
Izuku’s body bows, a wire pulled taut. The orgasm doesn’t crest—it detonates. A violent, gushing rush of clear fluid erupts from him, soaking Katsuki’s lap, their thighs, the sand and chair beneath them. It jets out with such force that a stray arc, glittering in the sun, spatters across Yo Shindo’s bare shins now stands a few feet away.
The man flinches, but his hand flies to the obvious bulge in his shorts. “Fuck,” he breathes, staring at the wetness on his skin.
Katsuki’s laugh is a dark, approving rumble against Izuku’s back. He doesn’t stop fucking, his hips driving through the squirting clenches, milking it. “Told you he’s a squirter.” With a grunt of effort, he pulls Izuku completely off his cock—the wet, sucking pop is obscenely loud—and manhandles him around in his lap until they’re chest to chest, Izuku’s back now to the ocean, his ass presented to their audience.
Katsuki’s hand slides down, fingers digging into the plush curve of Izuku’s ass cheek, spreading him wide. The cool ocean air kisses his exposed, pink hole. Izuku’s mind whites out. He’s being displayed. Offered.
“Pretty, isn’t it?” Katsuki growls, not to Izuku, but over his shoulder. He lines his cock back up with Izuku’s dripping entrance, nudging inside with a brutal, shallow thrust that punches a choked gasp from Izuku’s throat. “His cunt’s all mine. But this…” He taps a thumb against Izuku’s tight rim. “You wanna fuck my boy’s ass while I keep his pussy warm?”
Yo Shindo is already fumbling with his fly, his eyes glazed. “Yes. Christ, yes.”
Izuku watches, dazed, as the man shoves his shorts and briefs down, freeing a thick, decent-sized cock. It’s already leaking. The sight of it, the sheer wrongness of another man here, now, makes Izuku’s own cunt clench greedily around Katsuki’s girth. A fresh trickle of slick runs down his thigh. He spreads his legs wider on the chair, pushing his hips back. “Yes,” he hears himself moan, the word slurred. “Fuck my ass. Please.”
The stranger doesn’t need more invitation. He’s on his knees behind him, his hands hot and rough on Izuku’s hips. He spits into his palm, slicks himself, and presses the blunt head against Izuku’s resistance.
“Daddy,” Izuku whimpers, turning his face into Katsuki’s neck. The stretch is different, sharper, a burning intrusion that steals his breath. He feels Katsuki’s cock, buried deep in his pussy, pulse in response. He’s so full. He’s going to break.
“Look at me,” Katsuki commands, his voice gravel. Izuku forces his eyes open. Katsuki’s crimson gaze is molten, possessive, locked on his. “You want us both?”
“Yes,” Izuku begs, the burn in his ass flaring into a bright, blinding heat as Yo Shindo pushes in, slow and inexorable. “Daddy, please, DP me. Fill me up.”
Katsuki’s grin is all teeth. “Your funeral, baby boy.” He waits until Yo Shindo is sheathed to the hilt, until Izuku is shuddering, impaled on two thick cocks, his body stretched to its absolute limit. Then Katsuki slams back into his pussy.
The dual penetration is an earthquake. Izuku screams, a raw, shattered sound lost in the crash of the surf. He’s pinned between them, a live wire of sensation. Every nerve is firing. He can feel every inch of Katsuki in his cunt, every inch of the stranger in his ass, their rhythms conflicting, then syncing, a brutal, filling pulse that owns him completely.
Yo Shindo groans, his forehead dropping between Izuku’s shoulder blades. “Fuck, he’s tight. So fucking tight.”
“He’s greedy,” Katsuki grunts, his thrusts deepening, grinding. “Takes whatever he’s given. My perfect little slut.” He crushes his mouth to Izuku’s, swallowing his sobs, kissing him with a possessiveness that feels like a brand.
"Breed me," Izuku gasps against Katsuki's mouth, the words a shattered, wet thing. "Please, Daddy. Both of you. Fill me up. I want it."
"Fuck," Yo Shindo grunts from behind, his thrusts stuttering at the plea. "You hear that?"
Katsuki's crimson eyes burn, locked on Izuku's. His hips grind deep, a possessive circle that makes Izuku's cunt clench. "You want his cum in your ass while I pump my load into your womb? You want to be fucking bred by a stranger and Daddy?"
"Yes," Izuku sobs, his body arching between them, stretched and splitting. "Want your cum, Daddy. Want his. Want to be so full of you I can't walk. Please."
Yo Shindo's rhythm turns frantic, his grip bruising on Izuku's hips. "Gonna cum. Christ, he's squeezing me like a vice."
"You don't cum until I say," Katsuki snarls over Izuku's shoulder, the command absolute. "This is my boy. You're just borrowing a hole." He drags his tongue up the column of Izuku's throat. "You hear that, baby? You're just a set of holes for me to lend out. But your womb? That's mine. Always mine."
Izuku's mind whites out on the ownership, the degradation. He nods frantically, tears mixing with the sweat on his cheeks. "Yours. Only yours. Just let him… please, let him help you fill me."
Katsuki’s laugh is dark, approving. He nips Izuku’s earlobe. "On my count. You ready to be our little cumdump?"
Izuku can only moan, his body a live wire of impending release. He feels Yo Shindo’s cock swell inside his ass, the stranger’s breath coming in ragged, obedient pants. Katsuki’s thrusts turn slower, deeper, each one aimed at that deep, claiming spot that makes Izuku’s vision swim.
"Now," Katsuki growls.
Yo Shindo shouts, his body slamming forward as he empties himself in hot, pulsing ropes deep in Izuku's bowels. The feeling of being filled there, the wet heat spreading inside him, triggers a violent clenching in Izuku’s cunt around Katsuki’s cock.
Katsuki follows a second later, a guttural roar torn from his chest as he drives in to the hilt and floods Izuku’s pussy. Izuku feels it—the hot rush of cum, so much of it, the feeling mixing with the stranger’s inside his ravaged body. The overload tips him over the edge. His orgasm is silent, a seismic lock of every muscle, his cunt milking Katsuki’s cock through the pulses as he squirts again, a weak, dribbling stream that soaks their tangled thighs.
Izuku’s hands come up, shaky and weak, to clutch at Katsuki’s shoulders. He turns his face, nuzzling into the sweat-damp column of Katsuki’s throat, and presses a clumsy, open-mouthed kiss there. Then another. His lips find Katsuki’s jaw, his chin, finally his mouth. The kiss is less a kiss and more a claiming, a silent, desperate brand. He licks into Katsuki’s mouth, tasting salt and Katsuki groans, his arms tightening, his cock—still semi-hard and buried deep—giving a weak, interested throb.
They kiss like that for a long minute, Izuku’s fingers tangling in spiky blond hair, Katsuki’s palms sliding possessively over the sweat-slick planes of Izuku’s back. The world narrows to the wet slide of tongues, the shared breath, the feel of Katsuki still inside him. Yo Shindo might as well be a ghost.
A soft, clearing throat sounds from behind. Izuku feels Katsuki’s mouth curl into a smirk against his. They break the kiss, both turning their heads just enough to look. Yo Shindo is standing a few feet away, pulling his shorts back up, his face a mask of awkward comprehension. He gives a stiff, wordless nod, turns, and walks quickly down the beach toward the resort path, not looking back.
“Good, he got the hint.” Katsuki murmurs, his voice a rasp of overuse. He presses his forehead to Izuku’s, his breathing still uneven. “You okay, baby boy?”
Izuku nods, the movement making him acutely aware of the liquid weight in his gut, the sticky mess on his thighs. “More than okay.” His voice is shattered glass. “Thank you, Daddy. For… for all of it.”
Katsuki’s thumb brushes over Izuku’s swollen bottom lip. “Don’t thank me. You earned it.” He shifts then, hissing as he finally pulls his softening cock free. The sudden emptiness is a shock, a cold rush followed by the warm, immediate trickle of cum down Izuku’s inner thigh. Izuku whimpers, his cunt clenching to keep Katsuki’s cum inside.
“It’s getting late,” Izuku pants, resting his forehead on Katsuki’s shoulder. The sun is lower, the heat less brutal. “We need… we need to get cleaned up. Get ready for Natsuki’s birthday dinner.”
Katsuki grunts in agreement. He shifts Izuku off his lap, standing on legs that are, for a second, unsteady. He reaches down, picks up the discarded tropical themed dress from the sand, and shakes it out. “Arms up.”
Izuku obeys, lifting his trembling arms. Katsuki slips the dress over his head, the cool cotton a strange contrast to his feverish skin. He doesn’t bother with finding his bikini—there’s no point, it was cheap. Katsuki tucks himself back into his board shorts, the fabric tenting slightly with the aftermath. They are a mess. Sand sticks to the sweat and drying fluids on their skin. They smell like sex and ocean.
They gather their things in silence, the earlier frenzy replaced by a weary, sated quiet. As they approach the stroller parked in the shade of the umbrella, a soft, fussing sound emerges. Natsuki is stirring, his little face scrunching up before his bright green eyes blink open. He sees Izuku and his chubby arms immediately lift, fingers grasping the air. A clear, happy burble escapes him. “M-ma! Mama!”
Izuku freezes, his whole body flushing crimson. He can’t look at Katsuki.
Katsuki has gone very still beside him. “He just said…”
“I’m sorry,” Izuku whispers, rushing forward to unbuckle the baby, his hands fumbling. “I should have told you. He started… a couple weeks ago when I moved in. It just… I didn’t know how to tell you.” He lifts Natsuki out, cradling him against his chest, hiding his burning face in the baby’s soft hair. Natsuki immediately snuggles in, one small hand patting Izuku’s cheek, content.
Katsuki doesn’t speak for a long moment. Izuku risks a glance up. Katsuki is just watching them, his crimson eyes unreadable. Then, something in his gaze softens, melts. A warmth that has nothing to do with the sun spreads through his expression. He reaches out, not for Izuku, but to let Natsuki grip his finger. The baby holds on tight.
“You might as well be,” Katsuki says, his voice low, rough with an emotion he doesn’t name. His eyes meet Izuku’s over their son’s head. “His mother.”
Izuku’s breath catches. He can’t speak. He just holds Natsuki tighter.
Katsuki smiles. A real one, small and private, just for them. Then he turns, taking the handle of the stroller. “C’mon. Birthday boy needs his cake.”