Leonard McCoy was a doctor not a voyeur, but it was hard not to pay attention to two beings having sex in his sickbay. McCoy watched Kirk and Spock's vitals as they fucked behind a privacy curtain, and he was certain he was in the running for unluckiest doctor in the Fleet.
Sex pollen, of all things. Little spores floating around their systems compelling them to find physical release with each other or die. There wasn't enough alcohol McCoy could get his hands on to sufficiently numb the memories. The memory of his friends having sex, along with what the little gasps and moans Jim made did to his dick.
Spock groaned something in Vulcan. McCoy froze. Blood shot straight downwards to his groin and damn it, there'd be no way to hide the bulge in his uniform pants. That straight-laced, rules-loving, emotionless green-blooded alien was making uninhibited sex noises – how could he be expected not to get hard?
He gripped the sides of his armrests while his gently rocking hips pleaded for attention to his cock. Spock's noises were growing louder and more frequent, almost outdoing Jim's, and fuck McCoy never imagined Spock being capable of such a thing.
He couldn't take it anymore. The doctor pulled out his dick and furiously tugged and stroked himself. Spock and Kirk both made their final noises of release and their faint shadows collapsed together. The Vulcan rumbled something deep in his native tongue and Jim said something that sounded dangerously close to 'I love you.' McCoy came, biting at his lip to muffle his noise.
The pair moved about as to dress and clean up and McCoy tried his best to wipe away his own evidence with a sanitary cloth. Shirtless and more than a little tussled, the two of them pulled away the curtain and Jim grinned.
"Want to get these off us, Bones?" He asked, gesturing to the wires that attached them to the machines. One of Spock's obnoxious eyebrows shot up.
"Doctor, you have ejaculated?" There was something in his dark eyes that was somehow suggestive and with the way Jim looked at Spock and then smiled at McCoy changed his mind.
He might possibly be the luckiest doctor in all of Starfleet.