Tony's cock pressed deep into Steve again, the slide slick and hot. Bent over the back of the couch, Tony's angle was perfect, hitting Steve's prostate with every thrust. Steve shoved a knuckle between his teeth, biting down hard. He had to hold out - Tony had told him not to come - but he could feel the rising pressure of pleasure building deep in his gut.
"Oh god, Tony," he panted. "I can't -"
"You can," Tony chastised him. "Don't come." Tony kept thrusting, and Steve squeezed his muscles around him, trying to draw Tony along. If Tony came, he'd stop, or maybe he'd let Steve come.
Tony didn't reply, slamming deep and pressing a hand on Steve's back to pin him down. He was high and heady, lost in pleasure and subspace, and suddenly it was too much, he couldn't stop. Steve's hips jerked against the edge of the couch and he came, spilling down over the cushions with a broken cry.
Tony immediately stilled. "Did you just come?"
Steve nodded, cheeks flushing. "I'm sorry. I couldn't help it. You feel so good."
Tony slipped free and stepped back. Steve covered his face with his hands, feeling Tony's hot gaze on the mess he'd made. Then Tony's chest pressed against his back and his lips found Steve's ear. "Flattery won't get you out of that. I told you not to come and you did. What does that mean?"
"P-punishment," Steve choked, still vibrating through the aftershocks of his orgasm.
"Yup." Tony's hand skated down Steve's back then he grabbed his collar and eased him back off the couch. Steve's legs shook and he gripped the edge of the cushion to keep from just slipping down to his knees. Tony combed Steve's hair back from his face with his fingers. "You okay?" he asked softly.
Steve nodded. "It was just too good. I'm sorry."
Tony pressed a sharp kiss to his lips. "Go to the bedroom. Get on your knees in front of the mirror."
"Yes, Tony." Steve stumbled to his feet then shuffled into the bedroom. There was a thrill in the shame of having made a mistake. He'd tried, but he'd failed, and that should have stung, but knowing that Tony would make him pay for it contained his failure to the moment. Tony would punish him, and everything would be okay; he would be forgiven. For now, he was caught in the grip of anticipation, wondering what Tony would do to him this time, how he would make up for disobeying Tony's command.
Tony appeared in the room a moment later. He was dressed again, in his jeans and t-shirt, but his hair was tousled and there was a light sheen of sweat across his brow. Steve's only purpose was to bring him pleasure, and Tony was still unsatisfied.
Steve dipped his chin. "I'm sorry," he said again.
Tony stepped up and gripped a handful of Steve's hair then tipped his chin back up so he could meet his eye. "You're going to be a good boy and take your punishment, aren't you?"
"Yes, Tony. Whatever I deserve."
"Of course you will." Tony tugged Steve up. "Hands and knees. Face the mirror."
Steve adjusted himself until he was comfortable. He couldn't meet his own eyes in his reflection, though, afraid of the mix of humiliation and arousal he'd see there. Tony tugged open the bathroom door which they'd afixed another mirror to. It opened into the room on just the right angle that if Steve looked up, he'd be able to see the reflection of his face as well as the mirror behind him, showing his ass.
Tony stood behind him and stroked his hand over the curve of is hip. "What's your safeword?"
"You're allowed to come, but you're not allowed to move. You have to kneel there and take what I give you."
"Yes, Tony." Steve gripped a handful of the carpet and dipped his chin, sucking in air, bracing himself.
Tony appeared, crouched down beside him, and forced Steve's chin back up. "And you have to watch."
"Fuck," Steve hissed to himself.
Tony kneeled behind Steve, shifting around until Steve's view was unimpeded. He reached up and smacked his hand across the fleshy part of Steve's ass. Steve gasped and jerked forward then stilled himself. A red blush bloomed across his skin in the shape of Tony's hand, then faded almost as quickly as it came. "I'm going to keep going until you keep that lovely red glow, however long that takes." Tony reeled back and smacked again.
Tony peppered blow after blow over Steve's ass, shifting his aim just often enough that it wouldn't numb. It wasn't long before Steve's entire rear was stinging, cringing in advance of every strike. But it still wasn't keeping the blush, the super serum erasing it almost immediately.
Steve's cock was rock hard between his legs again, weeping onto the carpet. He was suddenly so close. He whimpered and bit his lip; if he came again, he'd be so sensitive, but Tony wasn't showing any signs of stopping. "Please," he begged.
"Not until you've learned your lesson," Tony hummed lightly. "I want you to feel this when you sit down to dinner tonight with the team, and I want you to remember it the next time you think you can just come without permission." Tony's hand came down again, the sharp shock of pain radiating across Steve's skin.
"God, Tony, I'm going to come again. Please."
"You can do whatever you want. As long as you don't move while I paint this ass red."
"Oh fuck -" Tingling pleasure rocketed down Steve's spine and settled low in his gut as another slap across his ass had him coming again, pulsing over the carpet. He was desperate for a hand on his cock, after two untouched orgasms, but he knew there was no chance Tony was going to touch him. Broken, gasping whimpers leaked out as Tony spanked him again and again, not even pausing to let Steve get a hold of himself again.
"Eyes," Tony snapped, and Steve shot his eyes open, not realizing they had fallen closed. Finally, finally, the marks from Tony's blows weren't immediately disappearing from his skin.
Tony smoothed his hand over Steve's abused ass then smacked him again. His handprint remained. "That looks beautiful," he mused.
"Thank you," Steve gasped out.
Tony spanked him again. "Have you learned your lesson, love?"
"Yes, Tony. Yes."
"You only come when I give you permission."
"Okay. Two more. Count them." Tony slapped hard across his rear, and Steve's fingers tightened in the carpet.
"One," he choked out.
"Good boy." The praise curled, warm and soft through Steve's chest, then Tony hit again, chasing away the glow with sparkling pain.
"There you go," Tony crooned softly. He petted down Steve's back then eased him back off his hands and knees, lowering him gently to his side on the carpet. "Good boy. You took that so well. You're so good for me."
"Always for you," Steve echoed back. He was deep, deep under, floating and disconnected. His ass hummed with pain but it was a soothing, background feeling, letting him know he'd done a good job. He'd given Tony what he asked for.
"God, you're gorgeous like this. Come on up - we're getting in bed."
Steve let himself be pulled to his feet then laid out onto bed on his stomach. Tony pressed down over him, the rough scratch of his jeans torture against Steve's abused skin. One finger found his hole, and Steve moaned and whimpered into the pillow when it pressed deep inside him. Tony sat back and there was the rustle of clothing and then his cock replaced his finger. Every thrust reignited the pain that jolted across Steve's backside.
"You're so slick for me, baby. How do you feel?" Tony hissed in his ear.
"Hurts," Steve moaned. Pleasure was building again but his cock was exhausted, unable to get hard. "Good."
"Oh yeah." Tony pressed deeper. "Clench around me, baby."
Steve obeyed, and a moment later he flushed with satisfaction when Tony cried out and spilled inside him. Tony stayed there for a moment, breathing through the aftershocks, then pulled back, touching a featherlight kiss between Steve's shoulder blades.
Steve's body was heavy and useless, limp on the sheets, his head up in the clouds and spinning. A sheet was laid lightly over his stinging ass and the lights dimmed. Tony tucked up beside him and kissed his face, running his fingers along the edge of the collar, down his neck, his arms, then back up to cup his face.
He kissed him softly. "Good boy."