Katsuki’s tuxedo jacket swallows Izuku whole. The heavy wool smells like smoke and expensive cologne, and the sleeves hang past his fingertips. Katsuki doesn’t even look at the discarded pile of Izuku’s clothes on the floor. He just scoops them up in one hand, then bends, sliding his other arm under Izuku’s knees.

Izuku yelps as he’s lifted, the world tilting. “W-wait—”

“Shhh.” Katsuki’s voice is a low rumble against Izuku’s ear. He adjusts his grip, cradling the petite, naked body wrapped in black fabric against his chest as if he weighs nothing. “You can’t walk. You’re shaking.”

Izuku is. His whole body is a live wire, humming with the aftershocks of something he doesn’t understand. He hides his face against Katsuki’s shoulder, the starched cotton of the hero’s shirt scratchy on his cheek. One of the main elevator doors slide open with a soft chime.

Katsuki steps inside, turning to block the view of the corridor with his broad back. The doors close, sealing them in mirrored silence. Izuku sees their reflection: a giant in a rumpled tux carrying a small, bundled form, green curls peeking out from the jacket’s collar.

“P-penthouse?” Izuku whispers.

“Yeah.” Katsuki’s eyes meet his in the mirror. They aren’t smiling. They’re assessing, possessive. “My place. Where we won’t get interrupted.”

The elevator begins to climb, smooth and silent. Izuku feels the shift in pressure in his ears. Feels the hard muscle of Katsuki’s arm under his thighs. Feels the damp, cooling stickiness on his own stomach, trapped under the jacket.

“Why…” Izuku starts, then loses his nerve.

“Why what, fanboy?”

“Why are you… doing this?”

Katsuki’s laugh is a short, harsh sound. “You told me you were devoted. I’m accepting the offer.” He shifts Izuku slightly, his big hand splaying over the back of the boy’s thigh. “Your little body just proved it. Squirted all over yourself for me. That’s devotion.”

Izuku flushes, hot and miserable. He had. He didn’t mean to. It just… happened. A wave of pleasure so violent it felt like panic. “I didn’t know… that could happen.”

“I know.” Katsuki’s thumb strokes his skin, a slow, deliberate circle. “That’s what makes you perfect.”

The elevator dings. The doors open directly into a sprawling, dark living room. Floor-to-ceiling windows show the glittering city skyline far below. Everything is sleek, cold metal and dark leather. It smells clean, like ozone and lemon polish. Nothing personal.

Katsuki carries him inside, letting the elevator doors whisper shut behind them. He doesn’t set Izuku down. He walks to a large, low sofa and deposits the bundle of clothes onto it. Then he turns, still holding Izuku, and walks down a short hallway.

He pushes open a door with his foot. A bathroom. All white marble and chrome.

Katsuki sets Izuku down on the cold marble countertop, the jacket pooling around his hips. He doesn’t step back. His hands stay on Izuku’s bare thighs, pinning him in place. With a foot, he nudges a lever on the massive sunken tub in the center of the room. Water begins to roar from hidden jets, steaming instantly.

“W-what are you doing?” Izuku whispers, his voice swallowed by the sound of the water.

“Cleaning you up.” Katsuki’s fingers trace the inside of his thigh. “Properly.”

He steps back then, and his hands go to his own clothes. The bow tie comes off first, a careless flick of his wrist sending it to the floor. He unbuttons his shirt, slow, methodical, his eyes locked on Izuku’s face. Each reveal is a lesson: the dense, scarred muscle of his chest, the flat planes of his stomach, the dark trail of hair leading down.

Izuku can’t look away. He’s seen Dynamight’s hero costume, the strategic glimpses of skin in magazines. This is different. This is naked. Real. The power in his shoulders, the old, silvery scars mapping violence across his ribs. Izuku’s breath hitches. His heart hammers against his ribs.

Katsuki undoes his belt. The buckle clinks. He pushes his trousers and briefs down in one motion, stepping out of them.

Izuku’s mouth goes dry.

Izuku stares, his brain short-circuiting. Katsuki is… massive everywhere. Thick thighs corded with muscle, a heavy cock resting against them that makes Izuku’s stomach clench with a strange, hot flutter. A slick, unfamiliar warmth blooms between his own legs, a sudden dampness that has nothing to do with the cooling mess on his stomach. He shifts on the cold marble, confused.

Katsuki’s eyes drop, tracking the minute movement. A slow, predatory smile spreads across his face. “Look at that. Getting all excited just from looking.”

“I’m not—” Izuku starts, but his voice is a thin squeak. He doesn’t even know what he’s denying.

“You are.” Katsuki steps closer, the heat of his body pushing against Izuku’s knees. He doesn’t touch him. Just looks down, his gaze like a physical weight. “Your little pussy is dripping for me. Can you feel it?”

Izuku flinches at the word. It’s crude, shocking. He feels his face burn. “My… my kitty?” he whispers, the childish term feeling absurd now.

Katsuki’s laugh is a low, dark sound. “Kitty. That’s cute. It’s called a pussy, fanboy. And yours is wet. That means it wants something.”

“Wants…?”

“Education.” Katsuki’s hands land on Izuku’s thighs again, his thumbs pressing into the soft inner skin. “You’re fucking clueless. It’s time for a lesson.”

“A lesson?” Izuku’s eyes widen, a spark of his old, eager curiosity cutting through the fear. “About… about bodies?”

“About sex.” Katsuki says it plainly, watching the confusion and dawning awe on Izuku’s face. “Your body. Mine. What they’re for.”

“My… my mother,” Izuku stammers, the words tumbling out. “She said I didn’t need to know. They had a class in school, but she wouldn’t sign the form. She said it was… dirty.”

“She was wrong.” Katsuki’s voice is absolute. A decree. “It’s biology. It’s power. And you’re drowning in it with no idea how to swim.” He leans in, his breath hot on Izuku’s ear. “You really don’t know anything, do you?”

Izuku shakes his head, a desperate, eager motion. He doesn’t. He’s spent years analyzing Quirk mechanics, hero tactics, but this—the aching throb between his legs, the way his heart races when Katsuki looks at him—it’s a complete mystery. “I want to understand,” he whispers, and it’s the truth.

“Good.” Katsuki’s hand slides up from his thigh, over the jut of his hip, and settles low on his stomach. His palm is searing. “Lesson one. This wetness?” His other hand dips lower, fingers brushing soft skin. Izuku jerks, a gasp tearing from his throat. “It’s your body saying yes. Even when your brain is scared shitless.”

Katsuki’s finger doesn’t push inside. It glides through the slick heat, gathering it, then retreats. He holds his glistening fingertip up between them. “See? That’s you. For me.”

Izuku stares at the evidence, his mind reeling. He made that. His body made that. Because of the man in front of him. The realization is terrifying. It’s also the most fascinating thing he’s ever learned.

“It’s called slick,” Katsuki says, his voice a low rumble. He brings his glistening finger to his mouth, never breaking eye contact, and sucks it clean. His tongue drags slowly over the knuckle. “Tastes like you. Sweet. Delicious.”

Izuku watches, mesmerized and horrified. His own body is a flavor on his hero’s tongue. “I… I made that?”

“You did. And what you did in the elevator?” Katsuki steps closer, caging Izuku against the mirror. “That’s called cumming. Orgasming. Climaxing.” He leans in, his lips brushing the shell of Izuku’s ear. “But what you did was special. You squirted. Gushed all over yourself like a little fountain. I’ve never seen a fanboy do that for me before.”

A hot, shameful thrill shoots down Izuku’s spine. “It’s… special?”

“Fuck yes, it’s special.” Katsuki’s hand slides back between Izuku’s thighs, his palm cupping him fully now. The heat is immense. “Watching you lose control like that, so fucking innocent, so surprised by your own body… it made me harder than any villain fight ever has.”

Izuku’s breath hitches at his touch.

“What does it mean?” Izuku whispers, his eyes darting down to Katsuki’s heavy cock, then back up to his face. “When you get… hard?”

Katsuki’s thumb strokes a slow circle on Izuku’s stomach. “We’ll get to my willy in a second,” he says, the childish word a dark joke in his growl. “First, you’re gonna learn all about your kitty.”

He pulls the tuxedo jacket from Izuku’s shoulders, letting it fall to the floor. The cold air hits Izuku’s skin, raising goosebumps. Katsuki’s hands turn him firmly on the counter, facing the vast mirror above the sink. Izuku stares at his own wide, frightened eyes, his flushed cheeks, his naked body dwarfed by the man standing behind him.

“Spread your legs,” Katsuki commands, his voice leaving no room for hesitation.

Izuku’s hands tremble as he obeys, placing his palms on the cold marble and shifting his feet apart. The movement exposes him completely in the mirror’s reflection—the soft curve of his ass, the delicate, hairless folds between his thighs, glistening with slick.

“See that?” Katsuki says, his hands settling on Izuku’s hips, holding him in place. He leans close, his cheek beside Izuku’s, both of them staring into the glass. “Your kitty has a real name. It’s called a pussy. Or a cunt.”

Izuku flinches at the words, his breath fogging the mirror. “It’s… ugly.”

“It’s not.” Katsuki’s finger appears in the reflection, pointing. “It’s perfect. Look. This here,” he traces the air just above Izuku’s skin, making him shiver, “these are your outer lips. They get puffy when you’re turned on. Like now.”

Izuku watches, mesmerized, as his own body is narrated. He sees the slight swell, the flushed pink skin.

Katsuki’s thumb presses into the soft flesh of Izuku’s thigh, his other hand coming down to frame the delicate, glistening folds in the mirror’s reflection. With a firm, deliberate motion, he spreads Izuku open.

Izuku makes a choked sound. The cold air hits his most intimate skin, but the exposure is nothing compared to the visual—the pink, swollen inner flesh, slick and shining under the bathroom lights, completely displayed.

“See that?” Katsuki’s voice is a low rumble against his ear. His index finger hovers, then taps lightly against a small, protruding nub at the top. Izuku jerks, a sharp gasp escaping him. The touch sends a jolt straight to his core. “That’s your clit.”

“My… clit?” Izuku whispers, staring at the tiny, sensitive part of himself he never knew had a name.

“It’s the most sensitive spot on your entire body,” Katsuki says, his finger beginning a slow, circular rub. The pressure is firm, insistent. “Rubbing it right… like this… will make you feel so good you’ll forget your own name.”

A whimper builds in Izuku’s throat. His hands slip on the marble counter. The sensation is overwhelming—a direct, electric line of pleasure that makes his knees buckle. His hips twitch forward, seeking more of the contact before he can stop them.

“There you go,” Katsuki murmurs, watching Izuku’s face contort in the mirror. “Your body knows what it wants. Even if you don’t.”

He rubs for another few seconds, each pass drawing a shaky breath from Izuku, before he stops. Izuku almost cries out at the loss. Katsuki’s finger trails down, through the wetness, and stops at a small, barely-there opening just below.

“This,” Katsuki says, his fingertip resting just above it, “is your urethra. Your pee hole. Where piss comes out.”

Izuku flushes, humiliation heating his skin. “Oh.”

“And,” Katsuki continues, his voice dropping, “this is where all that sweet squirt came from in the elevator. That wasn’t pee, fanboy. That was you. Coming apart for me.”

The memory of the elevator—the shocking, gushing release—floods back. Izuku’s stomach tightens. “It comes from… there?”

Katsuki’s fingertip presses against the tiny opening, a firm, teasing pressure that makes Izuku’s breath catch. “We’ll play with this hole later,” he rumbles, his thumb stroking the sensitive skin around it. “Make you squirt all over my face. But for now…”

His fingers slide down, through the slick, and find the main entrance. Izuku watches in the mirror, transfixed, as Katsuki uses two fingers to gently part the swollen, glistening folds, exposing the darker pink flesh within. The opening is small, tight, and visibly flutters under the cold air and the intense scrutiny.

“This,” Katsuki says, his voice a low, instructional growl right against Izuku’s ear, “is your vaginal opening. Your pussy. This is where a willy goes in. Where you get fucked.” He applies a gentle, downward pressure, and the hole yields slightly, opening wider. “And look. Deep inside. See that?”

Izuku stares, his heart hammering against his ribs. Past the initial ring of muscle, deep in the shadowed, wet channel, he can just make out a different texture—a small, dimpled circle of flesh. “I… I see it.”

“That’s your cervix,” Katsuki explains, his breath hot on Izuku’s neck. “The door to your womb. That’s where babies grow when you’re pregnant. When a man cums deep inside you, his seed hits that door. Tries to knock it down and plant a baby in you.”

A violent, confusing shiver wracks Izuku’s small frame. The concepts are too huge, too adult, that he should know, but it was kept from him. Pregnancy. Babies. Being filled. His head swims, but his body betrays him with a fresh, hot gush of slick that drips down his inner thigh. The evidence shines in the mirror.

“You’re so fucking wet,” Katsuki observes, a dark satisfaction in his tone. He releases the folds, letting them close, and brings his soaked fingers back up to Izuku’s line of sight. “All this, just from me talking. From learning about your own little cunt.”

Katsuki turns Izuku around on the counter, the boy’s back now pressed against the cold marble. He keeps one hand firm on Izuku’s hip, the other held up between them, fingers glistening with Izuku’s slick. “Watch,” he commands, his voice a low growl.

Izuku’s wide eyes fix on the wet fingers as Katsuki brings them down to his own soft, heavy length. He wraps his hand around the base, giving a slow, deliberate stroke, smearing the wetness along his skin. The contact makes his cock twitch, thickening visibly in his grip.

“I’ve been forcing myself to stay soft for your little anatomy lesson,” Katsuki says, his thumb rubbing over the tip, spreading the moisture. “But it’s time you learned about my willy. It’s called a cock. Or a dick.”

He guides Izuku’s gaze with his own. “This,” he says, his voice instructional, “is what it looks like when I’m soft. When I’m not turned on. When I don’t want to fuck.”

With his other hand, he pinches the loose skin at the tip, pulling it forward. “This is my foreskin. It covers the head when I’m soft.” He tugs at it, rolls it between his fingers, making the action clinical and obscene. “Now watch what happens when I let it get hard. When I get excited.”

Izuku watches, mesmerized and terrified, as Katsuki simply lets go. The control vanishes. The thick shaft in his hand swells rapidly, veins rising under the skin, the entire length hardening and lifting away from his body until it stands rigid and massive against his stomach. The foreskin pulls back on its own, sliding down to reveal the broad, flushed purple head, glistening now with a bead of clear fluid at the slit.

“See?” Katsuki murmurs, his breath coming slightly harder. He gives his cock a slow, possessive stroke from root to tip, his thumb smearing the pre-cum. “The skin retracts. The head gets exposed. It gets sensitive. Demanding.”

Katsuki’s thumb rubs over the broad, purple head of his cock, smearing the clear bead of fluid into a slick shine. “This,” he says, his voice a low, instructional rumble, “is the head. The tip. It’s the most sensitive part on me. Like your clit is for you.”

He pinches the skin just below the crown, making the slit at the very top pucker slightly. “This slit. This is where my piss comes out. And where my cum comes out.” He squeezes the head gently, and another, thicker droplet of clear liquid wells up and spills over his thumb. “See this? This sticky shit? That’s pre-cum. It gets my dick wet. Makes it easier to slide into tight little cunts like yours.”

Izuku stares, his mouth slightly open. The sheer size of it, the vivid color and the prominent veins, holds him in a terrified thrall. “It’s… so big,” he whispers, the words escaping before he can stop them.

“It is,” Katsuki agrees, no arrogance, just fact. His free hand drops to cradle the heavy, low-hanging sac between his legs. “Now these. These are my balls. My nuts. They hold all the cum. Touch them.”

Izuku’s hands tremble at his sides. He doesn’t move.

“Touch them, fanboy,” Katsuki repeats, the command leaving no room for refusal. “They won’t bite. They’re full. Feel how full they are.”

Hesitantly, Izuku reaches out. His fingertips brush the warm, loose skin of Katsuki’s scrotum. It’s surprisingly soft, but the weight of it is substantial, the twin orbs within shifting under his tentative touch. He flinches, but Katsuki’s hand covers his, pressing his palm firmly against the sac.

“Feel that?” Katsuki’s breath hitches, just slightly. “That’s a lot of cum. All stored up. The white stuff that covered your pussy in the elevator? That’s cum. Semen. When I shoot that deep inside you—past that little cervix door you saw—that’s what tries to knock you up. That’s what makes boys like you pregnant.”

A full-body shudder wracks Izuku’s small frame. The words are too much, too real. His hand tries to pull back, but Katsuki holds it there, forcing him to knead the heavy fullness.

“Lesson’s over,” Katsuki says, his voice a low rasp that cuts through the humid bathroom air. He releases Izuku’s hand from his balls, giving his own cock a final, slow stroke that makes the thick shaft jump. “We’re getting in the bath. Getting clean. Then I’m going to fuck this tight little cunt of yours until I’m empty.”

Izuku’s breath hitches. The words are too blunt, too graphic. He stares at the massive, veined cock standing rigid against Katsuki’s stomach. “F… fuck?”

“Yeah. Fuck.” Katsuki turns, his movements economical, and turns off the water in the deep, sunken tub across the bathroom. Steam has filled the room. “Putting my dick inside you. Pushing it into that wet hole you just learned about. Moving it in and out. That’s fucking.”

“But… it’s so big,” Izuku whispers, his voice trembling. He’s still perched on the counter, his thighs slick, his whole body humming with a confused, terrified arousal.

Katsuki doesn’t look at him, testing the water temperature with his hand. “It’ll fit. Your body’s already making the lube for it. See?” He nods toward Izuku’s thighs, where a fresh trickle of wetness gleams on the marble. “You’re scared shitless, but your pussy’s begging for it. That’s how this works.”

The tub is full. Katsuki turns back to Izuku. His crimson eyes rake over Izuku’s naked, shivering form. “Get in.”