If he didn't know better, Jim would have sworn Spock kept staring at him behind his back. It was ridiculous to even entertain the thought; after all Spock was…well. Spock, and he hadn't actually caught the Vulcan doing anything of the sort.

It was just…well, he usually just knew when he was being watched, and that familiar prickle at the back of his neck was rarely wrong. But Spock was hardly the type to just be staring at someone's back, was he? He could barely keep his eyes on Jim if there was paperwork or filing or goddamn regulation-memorising to be done, never mind if Jim wasn't even looking at him.

And yet….there it was again, the soft hairs at the nape of his neck rising as he felt a powerful gaze on him. He swivelled his chair casually, trying to look as though he was merely observing the crew at work, and of course Spock was bent studiously over his station, frowning slightly (or was that just his natural expression? Jim could never tell.)

Jim huffed out a sigh and turned back to the viewscreen, irritated. This had been happening for weeks now, and he was starting to seriously doubt his own body. Bones had found nothing wrong with him bar lack of sleep and an "attitude problem", whatever that meant, but it still kept happening. Kirk was starting to feel paranoid.

"Captain," Spock said softly, suddenly right at his shoulder, what the hell?

"Gaaah!…Spock, you can't keep sneaking up on me like that."

"I was merely walking, Captain. You were not paying attention." He sounded slightly accusatory, though his eyes held no anger. Vulcan idea of humour, Jim supposed.

Jim had learned a lot over the last few months- namely that Spock did have a sense of humour, even though he denied it; that Spock's eyes were human rather than Vulcan in that he could not mask his true feelings in them even when his face was a blank mask; and that he had a shitload more to still figure out about his odd First Officer, including how to get along with him. That last one seemed to be the hardest to manage, as despite several attempts, Jim seemed to be very good at getting on the wrong side of Spock, and Spock in turn was infuriating.

On a semi-related note, he had also figured out that he seemed to get off on being beaten up-mostly by Spock, which was awkward. Nothing said "I'm a capable, manly Captain and will kill you and/or dominate this situation" less than an uncomfortable erection in the middle of a fight. Or when being throttled, as that also mortifying experience on the bridge last year had proven. Thankfully Spock seemed to have either not noticed, or was mercifully sparing the Captain's blushes for reasons known only to him. Jim could still feel Spock's strong fingers around his throat, the Vulcan's muscles straining and shaking as he glared down at Jim, their bodies forced together. He could feel the Vulcan's hitching, tightly controlled breathing as the stronger man fought for some semblance of physical control. He saw again the world blurring, recalling the grey around his vision as Spock choked the breath from his lungs- and then the embarrassment and confusion as he realised he was harder than he recalled being in his entire life. Spock had looked confused, too, Jim thought he remembered- just a momentary flicker in his dark, furious eyes- but that could have been imminent unconsciousness talking.

He'd always known he liked a good fight, obviously…but there was a difference in getting off on a fight, and getting off on losing one. Especially when the worst reaction always seemed to be around Spock. In fact, he seemed to be becoming a little obsessed with that Vulcan.

"Captain."

"Wha-? Oh. Sorry, Spock. What was it?"

Spock gave Jim an inscrutable look before continuing. "I was informing you that we were coming into orbit of Ko'trus, Captain. We will be ready to beam down in approximately 23.6 minutes."

"Thank you, Spock."

"Captain, are you feeling quite alright?"

"Just thinking." Jim gave what he hoped was a winning smile, and Spock paused, frowning, before nodding and retreating to his station. It was lucky Spock was just a touch telepath and not the regular kind, or Jim would have sworn that Vulcan knew what he was thinking.

Ko'trus, as it turned out, was a horrifying death trap of a planet. Barely ten minutes in and they had lost two security officers, one falling to his death through a hole in the ground which spontaneously appeared, and the other setting herself on fire by touching an innocuous looking plant. Jim was determined to finish the survey, however, a decision which Spock strongly advised against.

"Captain, I must prevent you from continuing. Your life may be in danger. It is my duty to keep you safe and I am calculating an 89.6 percent chance of death on this planet."

"Well that's really very comforting, Spock," Jim said, bending down to poke his toe against a green rock. It promptly uncurled, waved slender pincers at the offending boot, and scuttled off. "Huh."

"Captain. I must protest."

"Protest away, Spocky. I'm still ignoring you."

"Please do not call me 'Spocky', Captain."

"Sorry, Pointy."

"Or Pointy," Spock continued with a hint of actual irritation. "We must beam back to the Enterprise."

"Last time I checked, Pointy, I was Captain." Okay, so maybe it was a bit too far, but Jim had been itching for a good fight for weeks, stuck on board with no enemies in sight.

Spock went silent and rigid, and the muscle in his cheek twitched slightly, which was never a good sign. Jim ignored him, continuing to take readings from the dull purple soil and humming gently to himself. Spock hated humming. He said it was the most illogical form of music.

Finally, Spock replied, in a clipped, precise tone which he somehow managed to make sound enraged despite its politeness, "You are Captain, however I am still your First Officer, and I insist that we-"

"Oh, go fuck yourself, Spock. I insist."

"Captain, if you continue, I will be forced to use physical action against you to ensure your safety as protocol requires. Also, I do not see the relevance, nor the practicality, of performing a sexual act upon myself at this time."

"Please do use physical action against me, Spock. I'm sure I will enjoy filing the report against you for assault on a superior officer."

"Very well."

Jim was sure he heard Spock growl before the Vulcan lunged at him, catching him off balance and tumbling them both to the dusty ground. He realised his game of "bait the Vulcan" may have been a bad idea roughly at the point when Spock's fist connected with his nose and he saw stars, tasting his own blood in his throat.

Fuck.

Jim pushed up blindly, catching Spock under the chin with a loose fist. It was like hitting concrete for all the damage it did to his first Officer, Spock barely even flinching before attempting a nerve pinch. Jim rolled away clumsily, getting to his feet and swaying dizzily before throwing himself head first at Spock and slamming him backwards. He was gratified to hear Spock's grunt of pain as the air was knocked from his body, the Vulcan immobilised for a brief moment as he caught his breath. Jim took the opportunity to punch Spock in the face, wincing as his knuckles protested but somewhat satisfied to see a trickle of green blood appear as he split Spock's lip. Spock shoved him backwards with a roar, straddling Jim's legs and beginning to pummel him thoroughly. Jim pulled at Spock's hair and dug his nails into the back of the stronger man's neck, but Spock had lost all semblance of control and went in for Jim's throat, squeezing mercilessly until Jim could hear his tendons creaking.

And that's when James T Kirk, Captain of the Enterprise and all-round cool guy, realised that once again, he was painfully hard. And this time Spock could not miss it, due to his current position right on fucking top of Jim. He flushed crimson, trying manfully to pass out before Spock could notice he was enjoying being unable to breathe, but it was to no avail as his body refused to let him die of shame.

Spock's hands faltered, then relaxed his grip without fully letting go, his eyes black as he frowned down at Jim gasping air back into his protesting lungs. He didn't move for what seemed like an age, seemingly thinking deeply. Unfortunately his body was still tight against Jim's, and his hands were still around the Captain's throat, so the problem wasn't going away any time soon. Jim cleared his throat painfully, his eyes drawn to a long ribbon of Vulcan blood winding its way down Spock's neck in a terribly distracting way, and attempted to act nonchalant. "Spock, if you're done killing me, would you mind letting me up?" His heart thudded in his ears and he was finding it difficult to stop staring at that neck, wondering what his skin smelled like and if Vulcan blood tasted like copper and if it did, what did Vulcan come taste like and would Spock make that growling noise if he was being fucked?

Spock blinked slowly, and then Jim could have sworn that he smirked, just a little. Except Vulcans didn't smirk, right?

"Of course, Captain. My apologies." He still hadn't moved, his hands still around Jim's neck, and suddenly he squeezed once more, at the same time grinding his hips- and his very obvious erection—against Jim's own, roughly, almost painfully. Just once was all he seemed to allow himself, before releasing his Captain and getting to his feet gracefully.

Before Jim could say a word, Spock turned, smoothing down his uniform and extending a hand to help the smaller man up, his face once again a mask of serenity.

It was as they beamed back up to the Enterprise that Jim realised something which made him blush all the way to his ears and wish for a spontaneous black hole to appear.

Spock was a touch telepath.

Spock had his hands wrapped around Jim's throat for the entire time he was thinking about fucking the Vulcan.

Spock clearly had either no problem with this mental scenario, or no control over whether Jim's thoughts affected his own body. Either way, there was only one reasonable response.

Shit.