It was tight...like a wet, silk band. Tight and quivering; hot friction. Why had they never done this before? "Is it-" Sherlock broke off and swore. It wasn't like him to suffer from such inarticulacy. "Does it hurt?"

"Ah...ah..." John was panting, his body pulled between two opposing and yet somehow allied forces. "No...doesn't...just a bit...good though."

If it weren't for the evidence, standing just before them, Sherlock would be quick to deny the actual existence of parallel universes. Further, the idea of ever having the ability to cross between them, and yet, there Khan stood-or really-a genetically enhanced but altogether still exact replica of himself. Not only from a different universe but from a different time period of that universe. There was no possible way for Sherlock himself to ever exist in the twenty-third century, but for whatever reason, this version of him did and apparently he was more deadly than Moriarty.

"More," John begged; of whom, didn't really matter.

Sherlock returned priority focus to the task at hand, as he gripped John's shoulder and pulled back for more leverage. His hips snapped forward and he groaned, the slide of his cock into the silky embrace of John's just recently virgin hole wrenching the sound from his throat. "Oh, God, John..."

-

"You've really never done this," Khan observed, his hand now working furiously over the length of their singular partner's prick.

John answered for them both with a stiff shake of his head, then managed to say, "I'm not...gay, actually-AH!-Sherlock!"

"I don't think he agrees with you," the displaced superhuman replied. He then picked up the hand John had been using to keep himself stable and placed it on his own erect member. Immediately, skilled fingers wrapped around him and began to tug slowly, adeptly. Khan smirked and whispered seductively, "I don't think you believe you. I certainly don't."

Khan pulled John forward just a bit with an arm wrapped loosely about the man's waist, giving his clever and far less homicidal counterpart a better angle for penetration and bringing himself and the doctor as close as possible. Their reactions were immediate. John's mouth dropped open, his eyes fluttered shut and his body bowed beautifully, inviting Sherlock even deeper. Sherlock, for his part, had finally come utterly undone. His face was buried in the soft hair at the base of the doctor's neck as he rocked his hips instinctively, biting his bottom lip to keep from making any embarrassing sounds.

Khan could hear them regardless, his auditory abilities quite enhanced and it only served to fuel his own desire. There was something achingly powerful in knowing that in another lifetime, in another universe, he could make those sounds. That he could give himself over so completely to a partner. He reminded himself again that until he was able to return to his own time, there was no war, no struggle to save his people and no annoying, spirited Captains to stand in the way of his revenge. He could...just this once, for just this moment...

He closed his eyes and gave into John's hand and his mouth...his soft, pliant body and sweet little sounds. Sherlock's groans of pleasure and abandon soon too became his own as he rolled his hips into the doctor's experienced hand. "Yes..."

-

John struggled for equilibrium as he was taken apart from the inside out by his best friend and his maniacal, superhuman other self. They'd been tracking a series of what had, at first glance, appeared to be vigilante killings. Links of criminal chains, torn asunder all over London—from ambitious street filth to the bosses of highly-organized crime rings. The clues had led them to Khan, which had led them to discoveries that went well outside the bounds of what John had previously considered possible reality.

How it had come to this...he was sure he'd remember eventually, but he was rather occupied-literally-at the moment. He really wasn't gay, but there were two of them now-two brilliant, manic self-proclaimed sociopath geniuses! And the sum total of their undivided attention and desire had somehow managed to fall upon him. Not that he was complaining. He was confused, but he wasn't complaining and he sure as hell wasn't unwilling. More like, curious, really.

John would have never guessed Sherlock desirous of sexual intimacy with anyone. Yet as they'd spent more time in Khan's presence, attempting to find a way to return him to his own universe, pieces of his friend's facade had begun to crack. John had noticed Khan's glances, had seen 'the look' and so of course Sherlock had observed it as well, and deduced. Jealousy on the consulting detective, John thought, suited him well.

Or, at least it did from John's perspective, otherwise how else would he have allowed it to escalate into this? Into anything at all? He maintained that he was still equally capable of buggery with women, but that perhaps he was willing to 'go gay for' Sherlock, and whatever other versions of him existed because this-Sherlock thrusting and quaking behind him and Khan squeezing and rubbing against his front-was all really quite agreeable to John's more than enthusiastic cock.

"Ah! Christ!" he shouted suddenly when Khan pulled him forward just a bit and Sherlock slipped in even deeper. He'd been waiting to experience prostate stimulation, while they were at it, and he had to admit it wasn't disappointing. There weren't any more coherent thoughts after that, and he closed his eyes and let go, let it happen. Too good to be regrettable.

-

Sherlock felt the tension ease form John's body as his gave himself over entirely. It was humbling. John wasn't submissive by nature and that he had allowed them to touch him at all... Sherlock closed his eyes and pressed a kiss to the back of John's head. There was no going back...and he knew they wouldn't want to-it wasn't how they worked.

His hips moved of their own accord, Sherlock's body seeking John's instinctively. They rocked, the three of them, together with John in the middle, pulling two formidable forces closer than they had any right to be but somehow managing to cancel what should have been an explosive collision.

When John tensed around him, Sherlock was already gone, lost to the frenetic drumming of his heart, the pulse of his cock as it spilled messily between them. His eyes were unfocused, his mind mesmerized by the sight of his counterpart and John coming together, their fluids mixing over John's bare chest.

They were certainly doing this again, Sherlock decided, still more than half high on endorphins, as many times as they could before Khan went back to his own universe to rule the galaxy or some such nonsense. It all sounded rather boring to Sherlock, but perhaps that was all there was for a high-functioning sociopath in the 23rd century.

For now, however, Khan seemed as content as he to lie there and bask in John's warmth and exhaustion. Yes, definitely again.