The air in the office was thick and silent, stale sweat and lemon polish hanging between them. Katsuki stood at the window, his broad back to the room, yanking the cord of the last blind. It snapped down with a final, metallic rattle, sealing them in dusty twilight. The only light now was a pale, guilty beam cutting under the door from the hallway.

Izuku stood just inside the threshold, still in his practice uniform, the short skirt damp and clinging. He watched his father’s shoulders, the tension in them like coiled cable.

“Lock it,” Katsuki said, voice a low gravel. He didn’t turn around.

The click of the deadbolt was deafening.

Finally, Katsuki moved. He circled the cold wooden desk and sank into his creaking leather chair. The red of his eyes was dark in the shadow, fixed on his son. He pointed to the worn plastic chair facing the desk. “Sit.”

Izuku’s breath hitched, but he obeyed. The chair was cold through the thin fabric of his skirt. He kept his hands folded in his lap, knuckles white.

Katsuki leaned back, the chair groaning. His gaze was a physical weight. “You jogged your laps.”

“You told me to,” Izuku whispered.

“I did. And now you’re here.” Katsuki’s voice dropped, intimate and dangerous. “Legs up. On your shoulders. Now.”

Izuku’s green eyes went wide. A flush spread from his freckled chest up his neck. He didn’t move.

“You wanted my attention, nerd.” Katsuki’s smile was all teeth. “You’ve got it. Every fucking ounce. Show me what you were teasing on the field. Show me what you made me touch.”

A tremble started in Izuku’s thighs. He swallowed, his Adam’s apple bobbing. Slowly, he hooked his hands under his knees. He leaned back in the cheap chair, lifting his legs, bringing his knees up to rest on his own shoulders. The short cheer skirt fell back, a pool of fabric at his waist.

Katsuki didn’t blink. He let the silence stretch, let Izuku feel the exposure, the cool air on his bare skin. The boy was already glistening, swollen from the denial on the field, from the jog, from this.

“Daddy,” Izuku breathed, the word a shaky, sexy thing.

“Use your hands,” Katsuki commanded, his own fists clenched on the desk. “Spread yourself. I want to see everything. I want to see how wet my son is for his coach.”

Izuku’s fingers shook as they moved from his knees, down his inner thighs. He bit his plush lower lip, his eyes locked on his father’s. His touch was hesitant, then deliberate. He hooked his thumbs, pressing the soft, hairless lips of his pussy apart.

The sound Katsuki made was raw, animal. A sharp inhale through his nose. Izuku was soaked, flushed a deep pink, his entrance clenching weakly around nothing. The scent of him, musk and salt, began to cut through the stale office air.

“Wider,” Katsuki growled, leaning forward now, elbows on the desk. His polo strained across his chest. “Let me see that pretty hole. The one you wanted me to fuck in my office.”

Izuku whimpered, but he obeyed, applying more pressure, exposing himself completely. The swollen bud of his clit peeked out, hyper-sensitive. A clear bead of arousal gathered, welled, and dripped down onto the plastic chair seat with a soft, distinct tap.

“Look at you,” Katsuki murmured, a feverish, possessive pride in his tone. “My brilliant boy. My perfect little slut. Dripping for Daddy right in his office.”

“I… I can’t…” Izuku’s arms were trembling with the strain of holding the position. His breath came in short, sharp pants.

“You can. You will.” Katsuki’s eyes drank him in, the hunger a living thing in the dim room. “Until I say otherwise. This is what you asked for. This is what you get.”

"Enough of that chair," Katsuki said, his voice a low crack in the silence. "On the desk. Now."

Izuku’s arms, trembling from the strain, lowered his legs. He stood on unsteady feet, the plastic seat slick beneath him. He moved the few steps to the cold wooden desk, the skirt barely brushing his thighs.

"Sit," Katsuki commanded, not moving from his own chair. "Facing me. Spread your legs. Show me again."

Izuku hoisted himself onto the edge of the desk, the cold desk biting into the backs of his thighs. He leaned back on his hands, then let his knees fall open, resuming the vulnerable, exposed pose. The air in the room was warmer now, thick with the scent of his arousal.

Katsuki’s eyes were black pools in the dim light, fixed between his son’s legs. "Good. Now use those clever fingers. Touch yourself. Show Daddy how you get off when you’re alone in your room, thinking about me."

"Daddy…" Izuku whispered, a protest and a plea.

"You heard your coach." Katsuki’s hand settled on his own thigh, a heavy, suggestive weight. "Do it."

Izuku’s breath shuddered out. He brought one hand down, his fingers glistening already from where they’d spread him open. His touch was feather-light at first, a tentative brush over his swollen clit. A sharp gasp tore from his throat, his back arching off the desk.

"Look at me while you do it," Katsuki growled, leaning forward, his massive frame crowding into the space between Izuku’s knees. "Eyes on me, nerd."

Izuku forced his wide, glazed green eyes up to meet his father’s. His fingers circled harder, slick and audible. The wet sound seemed to echo in the closed room. His free hand gripped the edge of the desk, knuckles bone-white.

"Talk," Katsuki demanded, his own voice rough. "Tell me what you’re thinking."

"I’m… thinking about your hands," Izuku panted, his hips beginning a tiny, desperate rock against his own touch. "On the field. How you… how you fingered me and then made me jog. It hurt. It felt so good."

"What else?"

"Your cock," Izuku moaned, the words tumbling out. "I see the outline in your pants. All the time. I imagine how big it is. How much it would… stretch me."

Katsuki’s jaw clenched, a muscle ticking. He watched Izuku’s fingers work, saw the flush spreading across his freckled chest, the way his small nipples were tight and dark against the thin crop top. "You’re dripping on my desk, you little slut."

"I can’t help it," Izuku cried, his rhythm faltering, becoming frantic. "Daddy, please, I’m close, I’m so close—"

"Stop."

The command was a whip-crack. Izuku’s hand froze, his whole body seizing with denied release. A sob caught in his throat.

“Did I say you could come?"

“No,” Izuku whimpered, his entire body trembling with arrested need.

Katsuki leaned back in his creaking chair, the predatory focus in his red eyes never leaving Izuku’s trembling form on the desk. He opened his own legs, the movement deliberate, dominant. “You watch now,” he said, his voice a gravelly command. “You’re gonna watch Daddy touch himself. Payback for your little show through the wall last night.”

His hands went to his belt. The click of the buckle was obscenely loud. He unzipped his track pants, and his cock, heavy and full, sprang free into the cool office air. It was thick, uncut, and already leaking, the flushed head glistening. His low-hanging balls rested heavily against the chair.

Izuku’s breath hitched, a sharp, wet sound. His green eyes were huge, fixated on his father’s hand as it wrapped around his own girth. “Daddy…”

“Eyes here, nerd,” Katsuki growled, his fist beginning a slow, punishing stroke from root to tip. His foreskin rolled back, revealing the slick head. “You’re not allowed to cum. You don’t get to. You just get to watch what you do to me.”

Izuku whimpered, his own exposed pussy clenching helplessly around nothing. A fresh trickle of arousal dripped onto the wood between his spread thighs. The sight of his father’s massive cock, the sheer size of it, the casual power in the way he stroked it, made his head spin.

“You see this?” Katsuki panted, his pace increasing slightly. The wet sound of his hand moving over his skin filled the space between them. “This is your fault. This is what my son does to his old man. Turns him into this.”

“I want it,” Izuku whispered, the confession torn from him. His hands gripped the desk edge so hard his knuckles ached. “I want to taste it. I want to feel it split me open.”

Katsuki’s jaw tightened, a low groan rumbling in his chest. “You’ll take what I give you. And right now, I’m giving you a view.” He sped up, his fist a blur, his other hand digging into his own muscular thigh. “Look at you. Dripping all over my desk. My good, smart boy. My perfect little cunt.”

Izuku was shaking, a fine tremble that ran through his entire body. He could feel his own climax, denied and desperate, coiling tighter just from watching, from the filthy praise. “Please, Daddy. I’m gonna… I can’t hold it—”

“You will,” Katsuki snarled, his own breathing becoming ragged. His hips pushed up into his fist. “You hold it, or I stop. And you don’t want me to stop, do you?”

“No!” Izuku cried, tears of frustration welling in his eyes. He forced his hips to still, every muscle locked in agony. His gaze was glued to the pulse visibly throbbing in his father’s cock, to the pearl of pre-cum that welled and smeared with each pass.

Katsuki’s strokes became shorter, harder, focused on the swollen head. A sheen of sweat coated his forehead. “This is mine,” he grunted, the words raw and guttural. “You. This. All of it. You made it mine.”

“Now you touch yourself again,” Katsuki growled, his own hand still moving on his cock, a slow, relentless piston. “Get yourself back to the edge. Show me how bad you need it.”

Izuku’s fingers dove back between his legs with a desperate sob. He was already swollen, oversensitive, his clit throbbing under his touch. He circled it frantically, his eyes locked on his father’s stroking fist. “Daddy, I can’t… it’s too much…”

“You can,” Katsuki said, his voice strained with his own building pressure. “You’re my good boy. You can take it. Get yourself right there for me.”

The room filled with the dual, wet rhythm of their hands. Izuku’s breathing was a ragged whine, his hips bucking helplessly off the desk. “I’m there, I’m there, please, please let me—”

“Look at me when you beg.”

Izuku forced his tear-filled eyes up. Katsuki’s red gaze was blazing, fixed on him with a possessiveness that stole the air from Izuku’s lungs. His father’s cock was a deep, furious red, slick and gleaming in his fist, his heavy balls drawn up tight.

“Now,” Katsuki commanded, the word a raw scrape of sound. “Cum for your Daddy.”

The permission shattered Izuku. A broken cry tore from his throat as his body bowed, seizing. But it wasn’t the quiet, contained climax he was used to. A hot, sudden gush erupted from him, a fountain of clear fluid that splashed across the space between them, coating Katsuki’s pumping fist and the thick length of his cock.

Katsuki’s hand stilled. His eyes went wide, his furious rhythm forgotten. “What the hell—”

Izuku kept coming, squirting in pulsing waves over his father’s hand, each spurt a violent release that left him gasping and shaking. The scent, musky and sweet, flooded the air.

The sight of it—the sheer, shocking abundance of his son’s release all over him—triggered something primal in Katsuki. A ragged roar ripped from his chest as his own orgasm seized him. Thick, white ropes of cum shot across his stomach and chest, mixing with Izuku’s fluid on his skin. He pumped himself through it, his eyes locked on Izuku’s trembling, spent form.

Silence fell, heavy and stunned, broken only by their heaving breaths. Katsuki stared down at the mess cooling on his torso, then at Izuku, who was panting, collapsed back on the desk, his tiny chest heaving. “You… you squirted,” Katsuki said, his voice hushed with something like reverence.

“I… I’m sorry,” Izuku whimpered, turning his face away, shame flooding his spent pleasure.

“Don’t you dare apologize.” Katsuki’s voice was low, awed. He looked at his own hand, glistening with both of them. “Look at this. You ruined me, you little slut. Absolutely ruined me.”

Katsuki stared at his glistening hand, then at Izuku’s heaving chest. He didn’t wipe it on his pants. He reached forward, his fingers still slick, and dragged them through the mess cooling on his own stomach. He gathered the mixed fluids—thick white and clear—on his fingertips.

“Look at me,” he said, his voice a low rasp.

Izuku, still panting, turned his head. His green eyes were glassy. Katsuki brought his wet fingers to the center of Izuku’s chest, right over his sternum. He smeared the fluid in a deliberate, possessive circle over his son’s freckled skin, marking the tiny swell of his pectoral. It was cold, sticky. A brand.

“You see that?” Katsuki murmured, watching his own hand work. “That’s you. That’s me. That’s what we are now.”

Izuku shuddered, a full-body tremble. “Daddy…”

“Shut up.” Katsuki’s tone held no anger, only a focused intensity. He spread the mess, coating Izuku’s skin, painting his pale pink nipples until they shone. “My good boy. My perfect, filthy boy. You ruined my desk. You ruined me.”

He leaned back, studying his work. Izuku lay marked and trembling, his chest glistening under the dim light. The scent of sex and musk was thick in the air. Katsuki’s own cock, spent and heavy, lay against his thigh. He made no move to cover himself.

“Did you know?” Katsuki asked, his eyes sharp. “That you could do that? Squirt like a fountain?”

Izuku bit his swollen lip, shaking his head. “N-no. Never… not like that.”

“Just me,” Katsuki stated. It wasn’t a question. A dark, profound satisfaction settled in his gut. “You only do that for me.”

“Clean yourself up,” Katsuki said, his voice rough but calm, a commander after a battle. “Get your ass home. Now.”

Izuku flinched at the dismissal. He pushed himself up and did as he was told like a good boy.