Written for trek_exchange over on LJ. Thanks to my girls for beta and support. They're lovely people.

Author's Notes: So I love Kirk/Spock for TOS, but I'm a total Kirk/Bones shipper in nu!Trek. But um, I couldn't figure out how to write a "Ponn Farr, Spock bottoms" fic for TOS. It's my first Kirk/Spock attempt... and why not write Pon Farr? Every trek writer does at some point, right? ;-)

Disclaimer: I write fanfiction of JJ's fanfiction of Roddenberry's Star Trek. Sooo... really Paramount owns everything.

Jim knew something was wrong when Spock didn't show up for his shift. Spock was always on time, was usually early. So for the commander to be over twenty minutes late for his shift told Jim that something was not quite right.

"Bones?"

The heavy sighed echoed even over the comm. "McCoy here. What is it Jim?"

"Spock hasn't shown up for his shift. Have you seen him this morning?"

There was pause over the comm and then McCoy's voice came back, tightly controlled. "He's on medical leave for the next week. Sorry Captain, the report must not have gone through."

Jim frowned and stared at the blinking light of the comm. Why was Spock on medical leave? Was there something wrong? He'd seemed fine yesterday, when they'd met to play chess. A little quieter perhaps, wound a little tighter, but nothing that had struck Jim as out of the ordinary. What could have happened between then and this morning's shift? McCoy sounded almost angry about it, whatever it was. Oh god, what if Spock was dying?

"Jim? JIM!" Jim snapped out of the downward spiral of his thoughts at McCoy's shout.

"What?"

McCoy sighed. "Is there anything else?"

"No, bridge out."

The comm shut down and Jim slouched in his chair, one hand propping up his head under his chin, the other drumming on the arm. He stared blankly at the view-screen. What could make Spock request medical leave? And without telling him? It couldn't be something horrible, otherwise McCoy would have sounded more worried. Or maybe McCoy was worried, but had been told not to tell Jim. That would make him sound angry. And McCoy had sounded angry. Well, maybe not angry, but definitely annoyed. But annoyed at Jim or annoyed at Spock? He couldn't tell.

Abruptly Jim stood, smoothing his gold shirt down over his waist. He was going to drive himself crazy, thinking about this. He needed to know what was going on.

"Sulu, you have the comm." He stated, striding towards the turbo lift.

Hikaru spun slightly in his chair, knowing smile on his face. "Aye aye Captain."

--

"Bones!"

McCoy looked up from the computer screen where he sat entering data. "Took you longer than I expected," he said gruffly, leaning back in his chair and crossing his arms over his chest.

Jim froze mid-step, processing that, then scowled at his friend. "I hate when you do that," he muttered, dropping into a chair. Jim's curiosity was without bounds, and McCoy had been expertly manipulating it since their first semester at the Academy. The worst part was that Kirk knew exactly what McCoy was doing, but he fell for it every time.

McCoy rolled his eyes, one side of his mouth quirking in a smile.

"So what's wrong with Spock?" Jim asked, leaning over and snagging a PADD from McCoy's desk. He flipped through the information, brow furrowing in confusion at the terms McCoy had started listing: plak tow, blood fever, psi-telepathy and Ponn Farr.

"I didn't want to tell you over the comm, Spock's embarrassed enough as it is," McCoy explained. "Well," he amended, "as embarrassed as a Vulcan gets anyway. It's not something they talk about with non-Vulcans."

Jim raised an eyebrow. "Vulcans not talking about something? Bones, say it ain't so."

McCoy huffed a laugh, shaking his head before his face smoothed and he became serious. "The destruction of Vulcan has really messed them up," he sighed. "From everything I managed to get him to tell me, Spock shouldn't be going through this for another five years or so. It's not just him, it's hitting a lot of the younger Vulcan males."

"Bones, you still haven't told me what it is!"

"Spock's starting the Vulcan mating season."

Jim stared at McCoy, eyes wide in disbelief, while McCoy stared back. A tiny grin started to creep across Jim's face. "Vulcan mating season?" He repeated.

McCoy rolled his eyes and leveled a glare at Jim, who immediately tried to sober his expression. "It's serious Jim! Vulcans need to mate and bond every seven years. Biological imperatives, survival of the species, that sort of thing. Now that their numbers have become so decimated, it looks like nature's kick-started the drive even earlier."

"And so... what? Spock needs to have sex and that's why he can't be on duty?"

McCoy hesitated, opening his mouth briefly then thinking better of it. He eyed Jim shrewdly for a moment before he finally shrugged. "Something like that."

Jim jumped to his feet, clapping his hand on McCoy's shoulder and grinning brightly. "Well why didn't you just say so!"

--

Jim whistled slightly as he walked to Spock's quarters. Really, this was nothing. Vulcan mating drive? No problem! Jim hadn't met a mating drive yet that he didn't like, he doubted he would now. Jim snorted to himself. Trust Spock to remove himself from duty because he was horny. He was probably meditating, trying to hide the drive under his Vulcan mask.

He entered his override code into the door, ready to tease Spock into losing a little bit of that control and convincing him that sex wouldn't be that big of a deal. However the scene he walked in on caused him to stop short.

The room was oppressively hot, causing sweat to bead on Jim's skin instantaneously. Spock sat sprawled in the middle of his floor, pale skin flushed green, completely naked and slowly pushing two fingers inside his own ass. Definitely not meditating then.

Spock's head snapped up at Jim's entrance, feverishly bright eyes raking over Jim's form, want and need fierce on his face. His movements stilled. "Jim..." he rasped, his voice dark and gruff and causing something hot to start curling deep inside Jim. "You shouldn't be here."

Jim shook his head, stepping farther into the room. "Bones told me what's going on." His eyes traveled over every inch of Spock's flushed skin, lingering on Spock's thick cock and where his fingers disappeared inside his ass. Jim swallowed hard and stepped closer. "I can help."

Spock shook his head, even as his body arched towards Jim. "No. The Doctor does not..." he hesitated. "The Doctor is not in possession of all the facts."

"What facts? You're in your mating cycle, you need to fuck... what else am I missing?" Jim dropped to his knees at Spock's side, knowing grin on his face.

Spock hesitated, anguish clear on his face. He struggled internally for a moment, and Jim reached out, smoothing his hand over Spock's shoulder. With a shudder and a gasp, Spock wrenched his arm away. "There is a bond needed. A permanent bond between two souls, a merging into one. I cannot ask this of anyone. Of you."

Jim stilled, hand still stretched out towards Spock. A permanent bond? While he had no problem having sex with Spock, did he really want a permanent bond with the man? They'd only known each other for a year. Jim sighed heavily, pulling his hand back. He raised his head to meet Spock's eyes, ready to apologize, and froze.

Dark eyes stared back at him and memories flashed through Jim. Memories of the other time line: battles, dependence, arguments, friendship, camping, love, sex, rescues, bonding, loss. Th'y'la. Memories of their own time line: arguments, battles, teamwork, admiration, caring, friendship. The possibility of more.

Want and desire slammed into Jim and he slid closer. Spock's eyes widened as Jim wrapped his hands around his shoulders and lowered his head. He nudged his nose against Spock's, pressing a feather light kiss to the side of Spock's mouth.

"Who said you have to ask?" Jim breathed, whispering, before covering Spock's lips with his own.

Spock froze minutely before surging into the kiss, lips parting and tongue snaking out to dive deep into Jim's mouth and explore every crevice. Jim pushed back, sucking on Spock's tongue and nipping at his lips, hands mapping every inch of Spock's skin. One hand slid down Spock's abdomen, ignoring the throbbing cock to slide down and behind, tracing the slick hole that Spock had loosened himself.

Jim moaned into the kiss as he slid one finger into Spock, the muscle yielding easily. It was hot and slick already and Jim easily slid in a second finger, crooking them slightly and pressing deeply. Spock ripped his mouth away from Jim's, breathing heavily, trailing kisses and nips along Jim's jaw as he pushed himself down on Jim's fingers.

"More," he breathed, biting into Jim's neck and Jim obliged, sliding a third finger in. He worked his fingers slowly, thumb rubbing against the tight ring of muscle. Spock groaned and writhed, trying to push Jim's fingers in deeper, faster.

"I will not break," he growled, ripping at Jim's shirt and trailing bruising kisses along Jim's collar bone.

"God, great, excellent," Jim breathed, stammering as he tried to undo his pants one handed. Spock's hands joined him and together they quickly got Jim's pants undone and shoved down his thighs. Jim's cock jutted out, purple and already impossibly hard, until Spock took him in hand and the warmth of his palm made Jim shudder.

"Shit, oh god, stop, wait..." Jim shoved Spock's hand away, pushing at Spock's shoulders. Spock followed the silent order, Vulcan strength yielding under Jim's hands until Spock was spread out before him on the floor, staring up at him with lust filled eyes and slowly stroking himself.

Jim bit his lip at the incredible scene, having to close his eyes and imagine Admiral Archer naked before he lost control. He yanked his boots off, shoving his pants and ripped shirt off before settling himself between Spock's spread thighs. Spock's legs instantly locked around him, dragging him closer. Jim braced himself on one hand above Spock, the other grasping his own cock and lining himself up. He raised his eyes to watch Spock's face as he pressed in.

Spock's eyes fluttered shut as he moaned and Jim had never seen his expression so open, so uncontrolled. He pumped his hips, sliding deeper with every thrust until he was all the way in, balls resting against Spock's ass, and he braced himself. He waited, breathing heavily, trying to control the urge to thrust and move and rip into the warm heat that gripped him. Jim raised one hand to Spock's face, tracing the angled contours of his cheek with his thumb.

"Move, Jim!"

Jim pulled back before shoving in. Spock's hips rose to meet his thrust, thigh muscles contracting as they pulled Jim closer. They easily found a rhythm, sliding slowly apart before shoving back together roughly. Jim shifted, gripping Spock's ass and changing the angle so his dick hammered against Spock's prostate. Spock's fingers gripped tightly, dragging Jim down into a wet opened mouth kiss, all tongues and teeth and no finesse except perfection.

Quickly Jim recognized the building heat in his balls. He pressed in deep, kissing Spock fiercely, and dragging his mouth to Spock's ear to nip at the sensitive tip. He pulled back, hips still thrusting, long and slow, to rest his forehead against Spock's.

"Do it," he breathed, eyes trying to focus on the dark ones below him.

Spock didn't hesitate, lost in his desire and drunk on the taste of Jim's skin. His hand pressed unerringly on the psi-points on Jim's face and the world exploded into a wash of color and light and feeling. It was everything and nothing, beginning and end, stretching out to infinity as their minds reached out and found the missing half, melding together to become one entity, as they were meant to be.

Dimly Jim felt himself thrust into Spock and climax, Spock shuddering around him in his own orgasm. But the feeling barely registered next to the euphoria Jim felt as he suddenly found himself whole.

---

Jim came back to himself slowly, senses rebooting as he realized he was slumped over Spock, head buried in his neck. He breathed deeply, enjoying the musty smell of Spock, himself and sex that permeated the room. He lay contentedly for a moment, before blinking in realization. He pulled back to stare at Spock with a surprised grin.

"Spock... are you purring?"

Spock stared up at Jim, dark eyes still bright with fever, though it had muted. The corner of his mouth twitched and he lazily stroked one hand down Jim's side. "No." An echo of humour, tinged with embarrassment echoed down the newly-formed bond at the back of Jim's head.

Jim stared down at his lover, no bond-mate, in amusement. He tentatively pushed his feelings of fond exasperation down the bond. "Liar."

"Vulcans do not lie," Spock murmured, rolling them so that he was braced on one elbow above Jim.

Jim grinned. "Bullshit," he laughed.

Spock ignored him, dropping his head to nip at the soft skin behind Jim's ear. His cock nudged at Jim's hip.

"Again?" Jim moaned, even as he dropped his head to give Spock more access to his neck. He felt the ripples of arousal from Spock's end of the bond, the desire to claim.

"Pon Farr lasts for several days," Spock reminded him, in between kisses and bruising bites at his neck and shoulder.

Jim shuddered at Spock's low tone and the flush of heat over the bond, feeling his own cock twitch in interest. He reached out blindly, fumbling for his pants. Spock stilled his movements, sensing his intent.

"Bones?" Jim gasped as soon as he found his communicator.

"Dammit Jim, I'm busy, this better be an emergency."

Jim smirked up at Spock, who raised an eyebrow in amusement. "I need to go on medical leave, Bones."

There was a pause from the other end of the comm, followed by, "Dammit Jim! How lon... wait no, I don't want to know. Medical leave, my ass. Three days." The comm chimed off.

Jim tossed the comm away, bringing his hand to Spock's side. He rested his palm against Spock's heartbeat, eyes lighting up in delight as the quick heartbeat elevated to an even faster rhythm.

"Three days off," he mused, tilting his head to mouth at the tip of Spock's ear. "How will we pass the time?" He bit down gently.

Spock growled low in his throat and pounced.

yikes. LOL I hope you liked it.