The first time it happens, they're all in the lab on the helicarrier. Tony is saying something Steve should be getting annoyed at, as it's probably a stab at his time as a - did he really say "Capsicle"? But he's put his hand on Steve's shoulder, normally a friendly gesture. His grasp is strong and steady and sends little jolts down Steve's arm and through his chest. He can feel the start of a blush on his cheeks and a stirring below his stomach and it's all he can do to focus on the conversation, but Bruce is talking in jargon that he can't understand anyway. He shuffles his feet uncomfortably. Tony glances at him for a split second, then smoothly takes his hand off, replying to what Bruce said. Steve is captivated by Tony's hands as they gesture while he talks. They're as animated as he is. He takes a deep breath to try to clear his head. Right, something about spectrometer calibration...
When Steve has his suit on, when he's Captain America, it's easier to deal with. There's a mental block that he's able to put up, so he's not as affected by his "problem". But when Tony extends his hand once the mess is over and the Asgardians are gone, he looks at it with trepidation, knowing what's going to happen. Three shakes, that's one more than could be considered decent, and all he can attempt to do is stoically look on as Tony drives off, and he has this nagging feeling from the way Natasha looks at him that she knows something's bothering him. He shifts uncomfortably on the seat of his motorcycle all the way back to S.H.I.E.L.D. HQ.
The third time, they're at a photo shoot for a press conference - Stark Industries getting a government contract to do something classified, Steve didn't ask. Once Tony beckons him to come up to the stage platform, the cameras all but explode with excitement. Tony's giving his practiced media smile and his arm is around Steve's shoulder again. It's not just a little blush this time. No, it's a full on rager that Steve has, and he just knows that someone will notice, with all the flashes going off. Steve does his best to ignore it and keep on a friendly smile, but when the PR rep announces the end of the event and they're off the platform, he pulls away from Tony just a bit too quickly.
A week later, Tony is helping Steve figure out how to use the internet on the Stark phone Tony gave him, because apparently Steve's hopeless. Tony is very enthusiastic about YouTube, which from what Steve gathers is a way to share funny and/or stupid videos. In particular, Tony likes a group called The Lonely Island, and makes Steve watch all of their videos. He thinks they're funny, albeit with far too colorful language, but then a song came on about – well, Steve hasn't caught up the latest slang, but this has to be about losing it in one's trousers. Tony's laughing and Steve can feel himself turning a bright shade of red. Despite the couple times that Tony's hands had brushed against his, he thought he had it under control, until now. And there's his arm around him again, as Tony's other hand hits the table repeatedly, punctuating his laughter. When the video finishes, Steve excuses himself. He barely makes it to the bathroom in time.
Over the next couple days, Steve is almost certain Tony is avoiding him, but that might be due to Coulson’s constant presence whenever they happen to be in close proximity. He remembered passing the agent during his escape from the rec room, so maybe he had told Tony off for being inappropriate? In any event, Steve’s thankful for the respite from Tony bothering him.
Unfortunately this does not last particularly long. They’re on a mission to infiltrate an island base – S.H.I.E.L.D. has intel on it being a hideout of a “Dr. Doom”. Natasha and Clint head in first, but the enemy is more prepared than they thought. The rest of the team rushes to the rescue, and the mayhem starts. They make quick work of the henchmen, and Steve’s crouching beside one who’s groaning particularly loudly (a shield to the stomach will do that), trying to gauge whether it’s worth it to haul him back to HQ for Fury to grill him. Steve notices the faintly beeping metal ball rolling up to them just in time to cover himself with his shield.
There’s a flash of light, far brighter than anything the explosion could have caused. Steve tries to open his eyes, and the room’s in fragments. He pulls himself up against the wall, his shield clattering against the floor - though the sound’s distant. There’s static in his earpiece, then someone’s voice, but he can’t make out what they’re saying.
Steve isn’t sure how long it’s been when he comes to. He keeps his eyes closed and lies as still as possible, attempting to asses where he is before he potentially alerts anyone to his consciousness. By the sound of it and the vibration, he’s probably on one of the quinjets again. He can hear Tony’s voice on his communicator. Apparently Natasha’s been injured. Then Tony says that it’s fine, he doesn’t need a medic, that he can “sort out Cap” when he comes to. No no no, anybody but Tony, he thinks frantically, there is no way that this will end well. He had unknowingly sat up in surprise, because Tony turns to look at him.
“Welcome back, Cap! Do you have something for grenade explosions? Because I heard about the training camp thing and I gotta say-”
Steve frowns at him in response.
“Well, we’ve got to make sure you’re okay, regulations and all, but the medics are with Natasha, so you’re stuck with me.”
Tony punctuates this with one of his Stark Smiles.
“I feel fine.”
Which was mostly true. A little dazed and shaken, but otherwise normal. But Tony wasn’t having any of it.
“Okay Cap, just look straight ahead, gotta check for concussion...”
Tony points a finger at Steve’s face, but nothing happens.
“Come on Jarvis, it’s time to phone home - oh there we go!”
A bright light beams out of the fingertip of the armor.
“Try not to blink.”
The face of the helmet slides down to cover Tony’s face, presumably so Jarvis could assist with the diagnostics. Even though it's covered by the suit, Tony’s face is still uncomfortably close. Steve chooses the most interesting seat opposite him to focus on, his eyes watering slightly.
“Well, your brain doesn’t look too rattled, now for vitals.”
Without warning, Tony grabs Steve’s forearms. It wasn’t a particularly abrupt motion, but it still makes Steve jump.
“Just try to relax.”
The forearms of the suit retract, and the metal coils under the outer armor unfasten from Tony’s arms, and begin to lock into place around Steve’s. He can feel the heat spreading, starting in his face and making its way down to his groin. They’re alone in the passenger hold of the quinjet and there’s nobody to save him this time and Tony is going to notice, he’s running vitals on him for crying out loud, it’s going to tell Tony everything.
The near minute of silence only adds to Steve’s agitation. The pants of his uniform are impossibly tight and he’s shifting in his seat. He’s certain that behind the helmet, Tony is staring straight at him.
“So Jarvis tells me sudden arousal isn’t a symptom of minor concussive trauma, which means this is either a coincidence or you’re very happy to see me.”
No no no, no no no no, this is not happening. Steve has no answer other than to gulp nervously, avoiding eye contact as the front of the helmet slides up.
“Is there something you wanna tell me, Cap?”
Steve decides not to dignify him with a response.
“Silent treatment, huh?”
The coils of the suit unlatch from his arms, and Tony stands up again. Steve stares defiantly at the seat opposite him the rest of the way back to S.H.I.E.L.D. HQ.
Once everyone’s debriefed and they’ve confirmed Natasha’s going to be fine, Steve heads to the rec room for his usual late night snack of coffee and a bagel. It isn’t until he’s already halfway to the fridge when he realizes he’s not alone. He doesn’t even have to turn to look, Coulson is in a meeting with Director Fury, Clint is still with Natasha, and Bruce is meditating in his room as usual after a mission, so there’s no way he’s going to avoid getting bombarded with more snide comments.
Tony gets up from the table, heading over to him to congratulate him on leading another successful mission. He puts his hand on Steve’s shoulder - this time, the contact is much more deliberate, his hand’s grasp more firm than before. It lingers way too long and Steve just wants to eat his bagel in peace. But he can’t help it, he’s at full mast in record time, so he uses the excuse of needing milk for his coffee to break away, even though Tony must know he drinks it black. Before he can move away, Tony’s hand brushes against Steve’s crotch, lightly grabbing for just a second, and there’s no mistaking what just happened and what he must have felt. Steve is too alarmed to grab Tony’s arm in protest.
“So it is true.”
“Don’t feign innocence with me, Cap. You’re turned on by me, aren’t you?”
“I am not having this conversation with you.”
“I’d like to see you try to ignore me, I can be very convincing you know.”
“There’s surveillance in here, I can file a report-”
“Already disabled. Do you think I’d make my move without setting my trap properly?”
That smug look on Tony’s face makes Steve simultaneously want to kiss him and punch him.
“I can’t control it, it’s not-”
“You don’t have to explain. But would it change anything if I said the interest was mutual?”
Steve glares at him.
“I’ll have a car pick you up in half an hour. Take the rear elevator to the 86th floor.”
“And if I don’t?”
Tony just smiles at him, then walks out of the room.
Tony’s bedroom is as grandiose as his personality. There’s an open bottle of champagne in an ice bucket on the nightstand next to the overwhelming four poster bed, and - are those silk sheets? Tony gets up from the armchair where he’s been nursing a champagne flute and heads towards Steve.
“Tony, what are we doing?”
“We don’t have to decide anything. I’m just offering to help you with your little problem. Well maybe not so little, now that I’ve had a feel...”
Tony circles around him, putting his hands on Steve’s shoulders, massaging them lightly.
“You’re so tense, Cap.”
“Steve is fine.”
He feels like there’s something stuck in his throat.
“Please,” he adds.
He’s already been half-hard from a mixture of excitement and anxiety on the elevator ride up, so it’s not long before his dick is straining against his pants again. He still isn’t over his disbelief that he actually took Tony’s invitation to come here. Tony’s hands wander down his back, one slowly reaching around to cup his crotch.
And then that’s it, he gives up. He spins around to grab Tony and kiss him with enough force that Tony’s eyes widen with surprise, then gradually narrow with desire. He’s grinding against Tony while he kisses him, his bulge almost painful now. Tony leads him slowly to the bed. He barely even notices tearing off his shirt and unbuckling his pants, his hands working automatically, and Tony’s struggling to keep up. He doesn’t bother to take off his pants, just fumbles with the fly of his briefs and his dick is finally free and it hurts how badly he needs this.
Tony pushes him down against the bed, pressing his lips against Steve’s while lightly grabbing his erection. Then his grip suddenly tightens and Steve’s moaning into Tony’s mouth. Tony breaks off the kiss and grins, admiring the sight of him laid out and so needy.
“Tony, don’t start - with the teasing crap-”
Not needing any further urging, Tony lowers his head and swallows Steve’s dick to the hilt, and it’s impressive, even for someone who’s probably so experienced, as the serum after all did make everything bigger. It’s all Steve can do to grab a fistful of Tony’s hair and hold on. Tony fondles Steve’s balls with one hand, the other pinching his nipples, and wow, he didn’t even know he was so sensitive there. He’s starting to thrust upward into Tony’s mouth when Tony stops, raising his head so a thin strand of saliva connects his tongue to the furiously swollen head of Steve’s dick.
“I wanna feel you in me. Not gonna waste something that gorgeous.”
Tony slides his boxer briefs off and reaches for the drawer of the nightstand.
“What should I do? I’m a bit new to...all of this.”
“Take your pants off and just watch me. And touch yourself.”
Tony slicks three of his fingers with lube, and efficiently works them into himself one by one.
“Normally I wouldn’t need to be so extensive, but you’re well, large.”
Steve has to stop touching himself to prevent from coming at the sight of Tony spreading himself open before him. Tony pulls his fingers out of himself and grabs Steve’s dick, spreading lube over it.
“I’ve never ridden a soldier before.”
Tony grins smugly as he lowers himself on to Steve, and Steve sighs as he slides deep into Tony’s ass. It’s gloriously warm and tight and Steve wants to flip him over and fuck him into the mattress until Tony begs, but he lets Tony take the lead, since he’s afraid of his strength mixing badly with his desire.
Tony leans back, supporting himself with his hands on Steve’s thighs, and really starts to ride him, his dick bouncing up and down in time with the thrusts of his hips. It’s too much for Steve, and his balls tighten up, and he’s pumping his load deep into Tony.
“Yeah, that’s it, you couldn’t hold out any longer, huh?”
“Don’t worry, I can come again.”
“They don’t call you the super soldier for nothing, then.”
That sly look is back, and Steve’s determined to wipe it off Tony’s face. He starts stroking Tony’s dick, which receives a heavy pant of approval. Tony’s hips are bucking wildly, his movements becoming more irregular, and Steve can sense how badly Tony must have wanted this too, his prize that was dangling before him for so long finally obtained. Steve gasps in surprise as Tony slides a finger into his ass, and he’s feeling something he’s never felt before. He wants more, a lot more.
“C’mon soldier, gimme another load.”
Steve obeys, the order making him come almost on the spot, his ass tightening around Tony’s finger, and fuck, how did he resist Tony for this long? Steve pulsing in Tony for the second time sends Tony over the edge, and he comes, spurting hot and sticky over Steve’s chest and abs.
Tony collapses next to him, looking wonderfully disheveled, glowing with sweat and satisfaction. He smiles and brushes his lips lightly against Steve’s.
“Aren’t you glad you gave in?”
“I can still file that report, you know.”
“I’d like to see you try.”
“You’re an asshole.”
Steve pulls him down for another kiss.
SR: TONY, STOP.
TS: What am I doing?
SR: YOU KNOW PERFECTLY WELL. NOW STOP IT.
TS: Can’t stop if I don’t know what is it.
SR: WE ARE IN THE BRIEFING ROOM, NOW IS NOT THE TIME.
TS: You really should get that capslock fixed, I can show you how.
SR: TONY, GET YOUR HAND OFF MY LEG. NOW.
TS: Okay, fine.
SR: PUTTING YOUR HAND IN MY PANTS POCKET IS ALSO UNACCEPTABLE.
TS: Isn’t this Wrecking Crew we’re learning about such interesting fellows?
SR: I’M SERIOUS TONY, STOP OR NO SEX TONIGHT.
TS: Like you can keep your hands off me.
SR: TONY I SWEA
TS: See, there you go.
SR: This isn’t funny.
TS: I agree, capslock is overrated. Good thing I fixed it.
TS: Oh hey, the brief’s wrapping up. Your quarters in 5?
SR: I hate you.