It starts out as a joke. Just a tossed-off one-liner about swapping.
And then it turns into something each of them starts thinking about separately. A lot. And conversations ensue in separate dwellings, a workroom, a government-issue sedan.
"I do, though. I want to watch him fuck you," Clint says, quietly, in bed, and Phil is incredulous, thinks he has to be joking. Clint laughs at his reaction. "Come on, like you wouldn't?" He palms Phil under the sheet and smiles, catlike. "I can tell you would. Your hero."
"You wouldn't be..." he gasps at Clint's touch, then his mouth. "...you wouldn't feel strange about that?"
"God, no. Who are you coming home with? Me, right? Do it. Please."
"He wouldn't want to," Phil says. "So it's kind of a purely...theoretical, academic discussion, isn't it? Oh. Oh, yeah...there."
But Steve does want to. Even before Tony started working on him like a teenage virgin in the cramped backseat of a Chevy Fleetline. He sees the way Phil flushes over his tie when he looks at him and thinks it could be...fun, watching him come completely undone.
Steve isn't as innocent as Tony likes to pretend he is (though he lets Tony think whatever he likes; his preconceptions are kind of hot.) So he puts up a front, lets Tony convince him, because Tony's eyes flared like fire when Clint kicked off the joke and he knows Tony's getting off on the idea as well as the convincing.
There's drinking, for Phil's courage. Just a few, before Steve's arm comes around his shoulder on the sofa and he smooths a hand over Phil's jaw with another, turns it, starts to kiss him, and Tony and Clint's conversation comes to an abrupt halt in the corner. They're keeping their distance, just a little, like they don't want to break the bubble Steve and Phil are in. Steve takes Phil's drink and sets it somewhere out of the way before his hands move to the navy blue tussah tie.
Steve's eyes are heavy-lidded with desire and his mouth is bruised from kissing by the time he unbuckles Phil's pants and eases them down, wraps his mouth around him, gazes upward. It's a little like a dream, and Phil's glad he's only had two drinks, won't forget this.
He's aware of the sounds of Clint's heavy breathing too -- Phil sees a little action out of the corner of his eye and glances over. Tony is busy with his hands on Clint, but Steve grips Phil's chin and turns him back, demands his attention. Then Steve is shifting him backward, getting him ready. Phil's fingertips graze over Steve's body with reverence, almost -- like he's touching a statue at a Florentine museum -- before tightening around the back of his neck, and its happening...Cap -- god, Cap -- is holding him down, fucking him, so slowly. Steve's face is serious, contemplative, his hand wrapping around Phil's cock, and he almost can't stand to watch, can't believe it's happening, with Clint's approval, no less. Phil moans, but holds back as long as he can until he can't, and he's coming then, too quickly, with his hands clamped tight on Steve's arms and then Steve's shuddering through his own release, raining kisses down the side of Phil's neck before he shifts and slides over.
Phil turns his head again and Tony's hair is a mess; he looks proud of his boy, and so does Clint -- Phil can tell it's going to be a long night, by the look on his face.
Steve reaches over him to the table, hands Phil his scotch with a lazy smile. "That was good, Agent," he says, and how are his lashes so long?
"It was an honor having you on board, Sir," Phil murmurs around the glass.