A/N: Another MCU Kink Bingo fill. This fulfills the "Steve Rogers Self-Cest" square

Tony stared at the two Steves in the doorway.

Two Steves. Holy shit.

"How did this even happen?" Tony asked.

He was pretty sure that when Steve talked about the mission he had gone off on with Natasha, there was nothing about people-splitting technology.

But here they were. Two Steves. One big, buff Steve in his Captain America uniform and one tiny Steve in the baggy shirt and slacks Tony remembered from his dad's old tapes.

"Bruce is working on it," Natasha muttered as she squeezed past both Steves and flopped down on the couch. "And he better get on it soon. Do you know how annoying it was to listen to both of them go on and on about you the whole flight back?"

Tony beamed. He had assumed maybe Steve's memories had been split by pre-serum and post-serum as well as his body. But he was pleased that both versions of Steve still knew and loved him. It was like having two boyfriends now. How had he gotten so lucky?

"Sorry," little Steve said with a twinkle in his eye that meant he wasn't sorry at all. "If your boyfriend was that fucking hot, you'd talk about him all the time, too."

"Language," big Steve snapped.

Tony stared at him.

"Oh yes," Natasha said with a curl of her lips. "He's pretty much two different people now. Which meant not only did I get to hear about how attractive they think you are, I also got to hear them argue about their sex lives."

"Is that so?" Tony rubbed his hands together gleefully. "How'd you get split? One of you likes cuddling, the other likes fucking? One of you likes dick and the other likes ass?"

"Language," big Steve snarled. "How many times do I have to tell you, Stark? We need to be professional in public."

Tony's eyes went wide. Stark? Steve hadn't referred to him as Stark in years. Not since they had admitted that there was more between the two of them than occasional bouts of angry sex after a mission gone wrong.

"We're not in public," little Steve pointed out. "And besides, what's wrong with a little public indecency anyway?" He winked at Tony.

Tony was beginning to have some inkling of what had happened. It seemed like big, buff Steve was his stern Captain America persona and little Steve was the sassy, rule-breaking little thing that had lied his way into the army.

This could get interesting.

"Public indecency is a crime," big Steve growled. "Punishable by law."

"Who gives a shit?" little Steve shot back. "It just makes the sex so much better. Nothing like the thrill of almost getting caught. Not that you know anything about amazing sex. You're too straight-laced for your own good."

Tony licked his lips as he watched the two sides of Steve's personality glare at each other. There was something really sexy about that glare when it wasn't directed at him. Who was he kidding? It was sexy even when it was directed at him.

Would the Sexy Steve Glare work on each other? Would all this tension between them result in gloriously intense angry sex?

God, Tony hoped so.

Who would top? Big, buff asshole Steve would be the logical choice. He could probably pin little Steve's tiny frame to the wall with his pinky. But if little Steve was made up of all of Steve's sass and mischief, there was no telling what underhanded maneuvers he could pull off. And it would be pretty hot to see that tiny little spitfire bring a man twice his size to his knees.

Tony could picture it so clearly. Big Steve on his knees, that perfect pink mouth wrapped around little Steve's cock, glaring upwards as little Steve fisted a hand in his hair and smirked down at him triumphantly. It'd be a rough blowjob, all teeth and intense suction. But Steve had always been a sucker for pain. It wouldn't take long for little Steve to reach climax, head thrown back, a beautiful flush across his face. And then big Steve would get up, shove his boneless body against the wall and have his way with him.

Or maybe little Steve could help the big guy take that stick out of his ass and show him how much nicer it felt to have a-

Tony jerked back to reality at the sharp sting across his face. "Ow, Nat," he complained, rubbing his injured cheek. "Did you have to slap me?"

"Apparently," she said. "It was the only way you'd stop drooling over the two of them."

Tony's eyes flickered back to the Steves. At the moment, big Steve had backed little Steve against the wall, his big hands pressed up against the wall, bracketing the little body in.

"Come on," Natasha said firmly. "Bruce needs your help in the lab."

"But, Natasha," Tony wailed. "This is a once in a lifetime chance. I'm never going to see Steve about to make out with himself again."

Big Steve jerked back. "That's not what's happening," he insisted.

Little Steve smirked and wound his hands around his bigger self's neck. "No, that's exactly what's going on," he said. He pulled big Steve into a heated kiss that quickly turned into a fight for dominance.

Natasha groaned. "Fine. Get it out of your systems. Then you're all going to see Bruce down in the lab so he can figure out how to reverse this thing." She stalked off towards the elevator.

Tony moaned happily as he watched the two of them go at it. There were just so many positions he could imagine the two Steves in. He couldn't decide which position he wanted to see most.

Maybe he could convince Bruce to hold off on the reversal for just a little while longer. Just so he could get the full experience.