The thing about Tony is, he's kind of a slut.
And by kind of he means definitely, and by definitely he means definitely, so it shouldn't come as a surprise to anyone involved that it takes him five minutes into meeting Dr. Bruce Banner before deciding yeah, tapping that. Then the guy actually talks and he's every bit as stupidly smart as his papers had made him seem and it's a show of willpower that keeps Tony from deepthroating him right there in the middle of Fury's shitty excuse for a lab.
He still thinks he should get a cookie for that.
Then his plans for getting laid get firmly derailed by Thor's crazy-hot-but-mostly-just-crazy little brother, and it's only when Tony notices exactly how Bruce's alter ego's shredded pants cling to his insanely huge dick that he remembers, because fuck yes. Jarvis is the only reason he doesn't get clipped by a Chitauri cruiser, and when the aftermath of the battle (and his near death and genocide of an entire race, but Tony is very carefully not talking about that, okay, look, he has this bottle of whiskey and everything is completely fine) he has a new plan.
Fucking Dr. Bruce Banner, definitely still on his radar. But first?
The problem is that seducing the Hulk requires the green guy actually being there, and Tony makes it all of a week into Bruce living with him before his plan to start with enormous green dick is sidetracked in favor of pinning the man against a wall and trying to get his tongue down his throat, namely because Bruce is brilliant and just won't stop talking and really no one should walk into his lab spouting physics like that and not expect to get made out with at least a little bit.
But the thing about Bruce Banner is that he's a huge buzzkill, and after five minutes of stupidly hot making out and Tony getting his hand down his pants, he'd called the whole thing off because he was worried the other guy might make a showing. Which, hello, really not a problem, but Tony had enough sense of self-preservation to not say that because he liked having Bruce around and if the guy ran back off to India or something he'd have to go fetch him and he had better things to do than have that argument, especially since it'd probably devolve into having to talk about his feelings and the fact that he maybe kind of sort of slightly wanted more out of this than a deep dicking from somebody who could whisper quantum mechanics in his ear.
So it was back to plan Seduce the Hulk. Which, really, Tony was fine with, except for the fact that Bruce was as in control as he was brilliant and while that'd be really really amazing if Bruce were displaying that control while, oh, he had Tony's dick in his hand and was stroking it slow and easy and refusing to let him come until he fucking begged for it, in this instance it was keeping him from getting laid, not helping him out with it.
Fortunately, three months in Bruce apparently decided that Tony's frequent reiterations that the green guy would be easier to get along with if he just got to come out and play every now and then might have a point. And that was how they ended up in the middle of fucking nowhere, population them, and Tony's promise to keep the suit on until he was sure how Hulk took him being there was completely not being broken. He'd waited all of five seconds and Hulk hadn't tried to smash, so even if he could hear Bruce's voice in the back of his mind going over exactly how stupid he was, Tony didn't hesitate at all in stripping his armor off.
"So we need to talk, big guy," Tony told him, shedding a gauntlet as he walked forward. Hulk looked down at him, eyes narrowing.
"Talk?" he rumbled.
"Yeah, not my favorite either," Tony replied, and he hit the mechanism to release the chest plate. The boots came next, and he got another good look at exactly why he'd almost gotten hit by an alien death-ray, and mm, definitely worth it. "Or we can skip the talking and go straight to the fun part.
The green guy just regarded him for a minute, like he was trying to figure out why he was standing here with no one trying to kill him and Tony just nattering at him, and he sat down with a whoosh of air out. "No want talk."
"Perfect," Tony said, and he closed the distance between them. And fuck, this close up the guy was really big, like, insanely big, and if he was as proportionate as Tony thought it was a damn good thing he'd spent plenty of time with lube and his toy collection before he'd suited up. "So I think we should fuck," he said.
Hulk just looked at him, and Tony rolled his eyes. "Fuck," he repeated slowly. "You. Me. Your dick in my ass. Sound good?" He thought about it for .2 seconds before deciding fuck it, and he put his hand on Hulk's thigh. Which, for the record, definitely hard as rock, and that was boding well for at least half of Tony's jack-off fantasies as of late. And hey, Hulk wasn't hitting him, which was good, because sometimes guys tended to do that even when the man coming onto them was Tony Stark, as he'd discovered three years ago in Vegas of all places.
"Talk too much," Hulk muttered, but he didn't move away from Tony's hand. Instead he just looked down at it, as if he were confused by Tony touching him, and Bruce got the exact same damn look sometimes and really could they not tug at his arc reactor when he was trying to get laid?
So really the only thing for it was to climb onto Hulk's lap, because explaining wasn't working, but he was pretty sure even giant green rage monsters caught on when you rubbed against them. And okay, maybe he was too big for Tony to get his knees around him, but he still wasn't getting smashed and Hulk seemed to be starting to approve of this, if the way his enormous hand settled on Tony's side and held him there was any indication.
"Yeah, just like that big guy," Tony encouraged, and he ground down against him in a way that made it blatantly clear that this wasn't his first lap-dance. Hulk grumbled, low and rough like stones scraping together, and fuck if that didn't make Tony's dick jump in his pants. He had a half-second of oh fuck I'm going to die before he felt Hulk push questioningly up against him, and okay definitely a grower not a shower and Tony was fucked in all the best ways.
And then Hulk was taking over, which Tony could really get on board with, making these low growls that were half-questioning, mostly aroused, and when he pulled at Tony's shirt Tony knew he had the right idea. Then there wasn't much more thinking for awhile, because apparently kissing a guy with a mouth at least three times as wide as yours was awkward but completely doable and he was going to have so fucking many fantasies about that tongue, he just knew it.
Then Hulk flipped him onto his back, and as the air went out of him Tony realized that Hulk had just been getting started and okay that tongue was getting underlined with stars next to it on his kink list, because Hulk wasn't deep-throating him but he'd curled his tongue all the way around him and that was so, so, so much better, slick and slightly rough and wet in all the right ways. He spread his legs wide, whining for it, and the shift of motion reminded him and yeah, he should probably get that out now. Tony got a grip on the handle of the thick, fat plug he'd kept in when he'd gotten in the suit (because giant green monsters + prep = not likely to happen) and pulled it out all in one go, and if he screamed as he did that was fine, because Hulk seemed to take that as approval of the way he was licking his balls and Tony was all over that.
And head, not exactly what he'd expected from the big guy, but the little part of Tony's brain that never shut up about science (just like the part that never shut up about sex, which was much much much louder right now) said something about pheromones and sweat and Tony didn't care as long as Hulk kept licking him like that.
He didn't even try to keep from whimpering when he stopped, then Hulk pushed his legs wider, grunted, and got the fat head of his dick against his hole and oh god Tony had underestimated so much when he'd picked out a plug and he knew he'd regret it later but he couldn't bring himself to even begin to now when he felt Hulk stretching him out, obscene and pushing the edge of physical possibility and completely fucking perfect. Then it was just spacing out, barely conscious for half of it, overwhelmed and drifting in a mix of pain and pleasure and the knowledge that there was nothing he could do about it and that was so gorgeous that the fact that Hulk was apparently a minute man didn't even matter, because Tony was coming so hard he wasn't sure if the stars were because his eyes were open or closed.
Then Hulk was shrinking down, still balls-deep inside him, and Tony groaned as his dick slowly went down to something more human-sized. "No talking," he slurred when he was sure it was Bruce he was talking to, and he waved a hand in the air. Then made another pass, because that one had gone kind of wide and were his limbs still working? "We agreed."
"I can't believe you," Bruce told him, but there was as much affection in it as there was disbelief and Tony knew he'd get chewed out six ways from Sunday later, but it didn't matter because right now Bruce was kissing him and it turned out that kissing a guy with a mouth that wasn't three times as wide as yours was pretty damn good, too.