Written for the

McShep PWP people, thought I would ease myself into the pairing!
Like most of their arguments, John has no idea how this one began. Probably something highly mundane like which terminator movie was the best one. But now they are shouting at each other, getting up in each others space, harsh words flying between them and its often like this. They know each other too well, know which buttons to press and what to fling at the other to cause maximum damage.
It takes him completely by surprise though, when Rodney's resolve slips and he slams John up against the nearest hard surface which just happens to be a corridor in the most secluded part of the city. God job no one can here the things coming out of his mouth. But its not like Rodney to loose his resolve, even though half the time when he looks at John he looks like he wants to punch him. And John knows its a look that's mirrored in his own eyes most of the time. But Rodney's fingers are gripping John's arms and he looks pissed, more pissed than John has ever seen him but there is something else under the anger, something that right now John doesn't want to try to decipher, but he can't help himself when he realises that Rodney's thigh has slipped between his own and is pressing up into his groin. The silence is thick between them and Rodney goes to apologise, surprise number two for this afternoon, his grip loosening until John darts his hands forward, tugs once on Rodney's body armour and pulls him back. They nearly head butt each other but Rodney's reactions are quicker than John gives him credit for and he stops himself from falling face first into John, his hands either side of his face.
John doesn't realise what he's doing until his lips are over Rodney's and he moans once. Neither of them move away though and Rodney moves one hand, sliding it down John's arm and gripping again, fingers digging into the skin hard enough to leave bruises and John can't bring himself to care. Because he can't believe he's never even thought about this, never entertained the notice that Rodney McKay would be kissing him back like its all that matters, like his life depends on it.
Its quick and messy, desperation fuelling the way John slips his hands inside Rodney's pants and grips his cock hard, and the angles wrong and awkward but it makes Rodney gaps and jerk his hips forward. John moves his hand, quickly, eliciting noises from Rodney he had no idea he could make as Rodney pressed his knee back into John's groin, hard again and John's head thumps backwards into the wall. Rodney's shifting of his hips isn't quite enough friction for John and his dying here, listening to Rodney's ragged breathes, his lips on John's neck and his hips shifting almost helplessly into John's hand, but then he stills, his whole body locking up against John and John feels the heat against his hand as Rodney shudders.
It takes him a few moments to get himself together enough to figure out that John is still hard, almost achingly so and Rodney shifts slightly, pulling far enough away to look at him.
John shakes his head once as a noise from the end of the corridor makes them both jump apart and Rodney scrabble at his pants, tugging them back into place while John wills his cock down.
“You owe me McKay.” He points one finger at him. Rodney smiles slowly, a mixture of satisfaction and amusement.
Rodney strode off down the corridor, ignoring the small Asian scientist who smiles in his direction and turned back to John. To anyone else it would have just sounded like a usual pointless John Rodney conversation. But John knew the hidden meaning behind the words and god if that didn't help his groin.
“And I'll pay, Sheppard.”