No. 21

Prompt: Stargate Atlantis, Rodney McKay/ John Sheppard, John isn't the only one with the Ancient Gene: Rodney has it too. Unfortunately, Rodney has a nasty reaction every time he attempts to use it.
http://comment-fic.livejournal.com/699131.html?thread=92173307#t92173307

Rodney tells everyone he doesn't have the gene. Since he was one of the earliest people involved in working on the Ancient control chair in Antarctica and has never sat in it and Beckett's mouth twists oddly whenever someone mentions giving Rodney the gene therapy, everyone thinks it's true.

John knows it's not. He's seen the shudder that passes through Rodney every time he reaches up to initiate a door lock. Rodney hunches his shoulders against the sensation, the gesture ever so minute that most people don't notice it, but John's a soldier is trained to watch the way people move, assess their threat level. Rodney's not a threat. He's on his way to being a friend, because almost dying to save each other is an excellent basis for friendship, and John doesn't want to see him hurt unnecessarily.

Sometimes John shirks his own duties to keep Rodney company in the lab and act as his human light switch. John has noticed that his light switch duties correspond to times when the rest of the science contingent is mad at Rodney and has left the labs to avoid throwing things at him, but he doesn't say anything, just obeys commands like, "Touch this," and, "Touch it again," and, "Think on," and, "Try thinking at it differently."

It all comes to a head when John is failing to initiate an important device that Rodney is sure will help save dozens of lives in the infirmary. Rodney growls, snatches it from him, presses his palm to it, and it comes to life. A shudder runs through his entire body, and John lunges at him, ready to snatch the device back, because it's hurting him, it's –

No. That's not pain. That's...pleasure. Rodney's eyes squeezed tightly closed, lips parted, flush spreading up his throat. That's –

John's dreamed of seeing that. Has a decade and a half in the military to pretend he never dreams of seeing it, because regs.

Rodney's panting, and John thinks, to hell with it, and he leans over, kisses Rodney, and Rodney kisses him back, and they end up on the floor trying to get into each other's clothes, and John mumbles, "The door," between kisses, and Rodney thinks it locked, which results in him bucking his hips against John's, and when they're finally naked and about to seal the deal, every Ancient device in the lab lights up.