I don't know whether Vulcans have canonically higher or lower body temperature, since I've read both versions, but this fic has it being canonically 103.00, so if you believe it's actually colder, then I formally apologize

[EDIT] Since every review has felt the need to tell me that Vulcan temp. is actually 91 degrees Fahrenheit, I've decided to just rewrite it so I won't have to look like an idiot over and over. Okay? Okay

Vulcans had a much lower body temperature than humans. It was only logical that he would be physically uncomfortable in Leonard's quarters without the human present, as the allocated temperature for the room was much lower than in his own. It was logical.

It was logical.

This was the excuse he was using to explain the sudden chill that had overcome him when the spoken of CMO had climbed from the cocoon of blankets they'd been curled up in to go to the bathroom and left Spock shivering in their bed. The sheets were still warm from their shared body heat, and the entire area smelled of Leonard, gave off his scent and his presence. It was a calming scent, of sun-kissed soil and the peaches he was so fond of and something uniquely Leonard that often left Spock in a state of relaxed ease, but the empty space and upturned blankets left from the human's absence had left the Vulcan victim to the cooler temperature. Leonard was immensely warm (in human standards), and gave off heat like a furnace, burning just below the surface of his skin. It was one of the reasons Spock had felt so comfortable in allowing him to hold him whenever they shared a bed, shuffled close together chest-to-back, in the same position they had been in before Leonard had gotten up. The heat would seep through his torso to warm him and lull him to sleep much quicker than when he was alone in his quarters. It was a prominent cause as to why they slept together more often than not as of late, as Leonard preferred Spock to be present when he awoke, much to the Vulcan's inner approval.

And yet, now, in his absence, Spock was left shivering pitifully under the cooling covers on his designated side of the mattress, trying to leech the remaining heat from Leonard's side before it evaporated into the air.

The human returned soon enough, much to Spock's satisfaction. He slid back beneath the sheets and wrapped his arms around him from behind, soothing the tremors left from the now escaping cold with ease. He grasped one of his hands with his own, eliciting a pleasant shiver from the Vulcan as he rubbed circles onto the back of it with his thumb and intertwined their fingers. His other hand slipped past the hem of his sleepshirt to rest his palm on his abdomen, warm and comforting on his skin. Spock felt the rest of the chill seep from him when he shifted his free arm to lock with the one around his midsection, and Leonard entwined their legs, the warmth spreading through him from each point of contact like a spark of electricity, and it buzzed deep in his gut, heavy and comforting. Indulgent kisses were pressed into the nape of his neck, his nose nuzzled into the hairs at the base of his skull, soft breaths puffing against his skin. He allowed a sigh to escape him, and felt his body sink into the embrace and the blankets with lingering fatigue. As Leonard's presence made quick work of chasing away the cold, he could feel the drowsiness return to his limbs, the way his eyelids were already drooping with heaviness. The embrace was snug and sheltered – cozy, as Leonard would say – and it melted down to his bones, digging in and relieving tension. And, since they had at least 5.46 hours before they had to report to their stations for the day, Spock could allow himself to succumb to the contentedness washing over him without a shred of guilt.

The human rested his chin on his shoulder before saying, voice rough with the sleep they had only recently woken from, "You're cold." It was a statement.

Spock shifted in his arms, enough to bump his cheek reassuringly against Leonard's chin. He kept his voice quiet when he spoke, no more than a murmur. "As you are aware, average Vulcan body temperature is approximately 8.6 degrees lower than humans'. It is only logical that I will eventually become cold when present within your quarters without proper clothing."

Leonard hummed noncommittally, shifting to press his lips against the column of his throat. "Never bothered you before," was mumbled against his skin, and Spock let out a sound of agreement.

"Admittedly, your presence has been startlingly adept at keeping my body temperature regulated. I find that, without contact, it drops rapidly when within your quarters."

Leonard chuckled softly in his ear, and he pressed closer against his back, the hand on his abdomen massaging soothing circular motions into the muscle. Spock shifted at the feel of it, hunkering down more comfortably within Leonard's arms and giving the hand that was entwined with his own a relaxed squeeze. They were both radiating contentment, something Spock had gotten used to after they had begun sharing a bed, of which was steadily becoming a more and more common occurrence. Moments like these had become something Spock cherished; for them to merely lie, tucked between the blankets, slowly drifting in and out of consciousness, satiated and peaceful. With how often their daily missions tended to take unsatisfactory turns, Spock had learned to treasure the quiet moments they shared on and off duty, how Leonard's arms felt around him, cradling him against his broader chest like a beloved heirloom. He tended to wallow in the affection for as long as he could. Leonard never brought it up, of which Spock was grateful for.

"Y'know, we can always sleep in your quarters instead of mine, if it'd make you more comfortable." Leonard's voice was nearly a rumble, thick with his accent, the one that came out whenever he was heavy with exhaustion or intoxication or happiness, and the one Spock secretly adored. It seemed to come out frequently when he was in the Vulcan's presence. Spock liked to imagine it was because the human was becoming significantly more comfortable with him the more they continued to establish their relationship. He was not altogether certain, and therefore did not feel free to ask, but he could imagine.

"Unnecessary," he told him, "I find your quarters satisfactory."

Admitting that the way Leonard's unique scent was embedded within the walls and made him feel secure in a way his own quarters no longer could was out of the question, but from how Leonard chuckled again – the rich, warm chuckle he seemed to only use when they were alone – the human had likely suspected something of the sort. "Well, if you're cold in here, then you're probably freezing out on the rest of the ship."

The assumption was not as far from the truth as Spock would like. The rest of the ship was set to be cool by human standards, to make sure none of the technology overheated. To a Vulcan, it was positively chilling, not cool. It was the reason Spock wore two undershirts instead of the standard one, and even then, he still found himself having to stifle the occasional shiver when he passed under an air vent and was hit with a sudden wave of freezing cold air. The temperature usually left his fingertips and the points of his ears numb, as they were the most sensitive to the climate change, but he couldn't exactly request that they turn up the moderated heat simply because he was cold. It would make the rest of the crew uncomfortable, and possibly damage the engines. It was logical to ignore it and move on. It had left no lasting effects on his health or physical performance, and so there was no need to contact anyone about it. It was not severe, and therefore not a problem.

Except, to Leonard, it seemed like it was. He was glossing over his concern with amusement, the way he tended to when something bothered him, and – while Spock would usually take the time to question him of his reasoning for doing so – by this point in time, he was beginning to sink pliantly into a soft, lulling doze. He could still hear him when he spoke, his mouth mere millimeters from his ear, could still pick up the words that were being said and the meaning behind them, the well-meaning concern for his comfort, but they were slow for his mind to articulate properly in his contented state.

"Tell you what," the human began, voice playful, and Spock forced his hearing to perk up in an attempt to pay more attention, despite the way his mind was just starting to drift in a sea of drowsy calm. "I'll let you borrow one of my tunics tomorrow. It's the same color; you can wear it for the day and see if it helps. That work for you?"

Spock hummed quietly at the suggestion, and answered back a few moments later, "I believe that will suffice."

Leonard chuckled again, and shifted enough without disturbing their embrace to press a kiss to his temple. Spock was lulled back to sleep by the feeling of Leonard's strong, rhythmic heartbeat thrumming against his back.

Spock could not say that he was not genuinely surprised that Leonard remembered their sleep-addled conversation when they woke up approximately 5.13 hours later. Leonard merely snorted and offered him his crooked smile from where he stood beside his dresser, removing – not the usual one – but two medical blue tunics when Spock admitted so. "My memory's not as good as yours, but it still gets the job done." He tossed one of the tunics to him, of which Spock caught with ease from where he sat propped up against the pillows and headboard, unfolding the blue fabric and eying it speculatively. The only obvious difference between it and Spock's own science officer tunic (of which sat, neatly folded with his two black undershirts, pants and boots on the small bedside table at his side) was the fact that it was at least three sizes too large. Leonard's frame was broad compared to his leaner physique – it was the main reason the human was the 'big spoon' when they shared a bed – but the extra cloth would be more of a comfort than a hindrance, Spock believed. Knowing that Leonard had willingly let him borrow and wear a piece of his clothing made a ball of warmth burst in his chest.

He allowed the pleasant feeling to spread from his chest throughout the rest of his body, and it settled in his stomach with a comfortable weight as he surveyed the rest of the tunic. He'd inspected the blue cloth before, of course, albeit while Leonard was wearing it (he'd inspected it thoroughly, in fact; the way it clung to him, the way it folded and twisted when he pushed the sleeves to his elbows, and so on). It was quite different doing so without Leonard's firm torso beneath the fabric, but it did keep him from being distracted as easily. He could see the Starfleet medical insignia attached to the cloth, the lieutenant-commander rank stitched into the sleeves. He would have to conceal those, somehow. He felt a sense of relief that he would be working predominantly within the science labs for the day for his weekly check-in; he was unneeded on the Bridge until the day after. However, there was also a sense of disappointment, that he would be unable to… for lack of a better expression, 'show off' that he was wearing his lover's tunic. The sense left him with a puzzled downturn of his lips; it was illogical to be disappointed over something as simple as clothing, of showing off clothing, clothing that wasn't even his, that was his lover's, that he was going to be wearing in public for the entire crew to see and witness. The thought left him with a warm humming sensation just below his ribcage, a sensation that made the puzzled frown wipe off his face in place of relaxed calm, when Leonard returned to the bedside, snapping his fingers in front of him with a fond, if exasperated, smile. He was already dressed.

"C'mon; we have a few minutes to hit the Mess before first shift."

Spock nodded, folding the sheets back away from his legs and stifling the shiver that would have otherwise escaped when he swung them over the side to stand. Leonard had acquiesced in turning the heat up, but it was still rather cool without the warmed blankets to protect him. He took to changing from his sleepwear into his uniform as swiftly as possible. If he could feel Leonard's eyes paying particular attention to his bare chest and legs as he changed (as usual), he didn't mention it.

When he tugged Leonard's tunic on in place of his own, he felt himself relax almost instantaneously. The hem nearly stretched past his hips, the cuffs almost reached his fingertips, and the collar was loose around his throat, but the cloth was thick with Leonard's scent, covering him with it, soothing him, and he found himself breathing it in eagerly before he even realized he had. When he turned back to Leonard, the human was staring at him with an amused sort of expression on his face, eyes filled with an affection Spock could feel radiating off of him. There was something else there, as well; possessiveness, a soft undercurrent of lust, but he ignored it as much as he could. Leonard emoted almost constantly. Spock was used to feeling the pounding current of emotions when they were in close contact, buzzing pleasantly just under his skin and keeping him grounded, even when they were on opposite sides of the ship. They had often been a cause for distraction, especially when an emergency cropped up and Leonard became taut with stress, and so Spock had learned to block them into a dull murmur when he worked. However, when they were so close – in Leonard's quarters, no less – it was certainly not as easy. It was actually rather difficult.

Of course, Leonard had no idea that he emoted so strongly, all the time. Spock merely strengthened his mental shields, allowing the affection and possessiveness pouring from the human to become a backdrop, simmering lowly at the back of his mind, as he sat on the edge of the mattress to pull on his boots. He could hear Leonard shuffling behind him from the other side of the bed, moving from the bedroom into the rest of the quarters to gather together his PADD and the other supplies he would need for his workday. Spock had memorized his schedule, if only to know when Leonard would be free and he could visit without interruption (the nurses in Sickbay were already used to his presence, and more or less left them to their devices when Spock arrived with food after the human had been in another five-hour emergency surgery, or when he dragged him from his office and the logs of paperwork that needed to be filled to get an actual night's rest).

When Spock stood and rolled up the cuffs to free his hands and hide the rank stitched into the fabric, he removed the medical insignia from where it was pinned to the cloth to replace it with the science officer one that had been attached to his own. After retrieving his own PADD, he followed after Leonard into the adjacent corridor to head to the Mess Hall.

The day was mostly uneventful. After breakfast (where Jim had not joined them, as he usually would have; he would not have to be on the Bridge for another hour, and so Spock assumed he was still asleep), they went their separate ways – Leonard to Sickbay and Spock to the Science Wing. They had agreed that Spock would bring lunch from the Mess at 1200 hours, when Leonard would have an hour of free time between the annual Vanarien Flu vaccinations the crew had to be given. Spock was scheduled for his own vaccination the next day, and so it would be the only time they would see one another until their shifts ended.

No one in the Science Wing noticed that the tunic he was wearing was not his own. He'd had to fold the sleeves up to his elbows to continue his work, of which consisted of, essentially, dissecting the overgrown carnivorous plant they'd brought in from Hels'thm V with the permission of the natives the day prior. He was the only one with the amount of strength needed to crack open the plant's fortified shell, and had therefore been the only one assigned to it while the ensigns around him scurried about, comparing notes and studying the other plants they'd been given that weren't as dangerous. Because of his rolled up sleeves, no one was privy to the lesser lieutenant-commander rank stitched into the fabric. When combined with the science officer pin in place of the medical one, no one was any the wiser.

The privacy left Spock with a feeling of calm throughout the day. The tunic was still thick with Leonard's scent, heady and sweet and nearly overwhelming, but not to the point where Spock could not work. In fact, the scent left him more at ease. He felt secure; the tunic, though loose, felt snug, and wrapped around him just so, in such a way that he could imagine it was Leonard's arms and not his shirt that encased his torso. He felt a sense of comfort, of stability, that pervaded almost every other thought he had that didn't have to do with work. The sense only grew after he shared lunch with Leonard that afternoon; the human was somewhat annoyed over the engineering ensigns' penchant for burns and the fact that he'd had to treat three of them already that morning, but indulged him with Vulcan and human kisses nonetheless. They left him nearly giddy when he left Sickbay to return to the Science Wing, and it was a feeling he had never been privy to in his life.

He even managed to finish up the dissection early, and – instead of finding something else to bide his time with, as he usually would have under other circumstances – he chose to retire to his quarters (or rather, Leonard's quarters) an hour before the human would. It was often the other way around, but Spock had found himself drifting pleasantly in a sea of serenity the entire day. He could indulge himself and retire early just this once, even if the science ensigns seemed genuinely surprised that he was doing so.

When he arrived at Leonard's quarters, the temperature was much warmer than it had been in the morning. Spock was hit with the wave of heat as soon as he keyed open the door, and he felt his breath leave him in a rush as blood returned to his fingers and the tips of his ears. He stepped past the threshold, and only allowed himself to slump with relief when the door slid shut behind him with a hiss. He knew that Leonard had not yet returned – there were still ten vaccinations left in his schedule – but the fact that he'd taken time out of that schedule to return to his quarters and moderate the heat for him left the Vulcan with a slow burning happiness in his chest. The feeling was almost as uncommon to him as the giddiness, but he pushed it to the side in favor of moving into the bedroom and removing his boots.

As he was changing into his sleepwear, he found himself unwilling to remove the tunic once it came time, his fingers hovering over the hem of the fabric. He dutifully ignored the sense of loss that pervaded him when he tugged it off and followed it with his two undershirts, neatly folding them and placing them back on the bedside table. But, even when he shrugged on his sleepshirt and climbed into bed, settling in against the pillows with a PADD (as it was still too early for him to be shutting down for sleep), he found his mind drifting back to the tunic, of which was sitting atop his pile of clothes on the bedside table, just within his reach. It was a strange feeling; not being able to focus on simple work because of a piece of clothing. After all, reading over the notes the ensigns had taken earlier that day should not have been that difficult.

And yet…

He set down the PADD and reached over, picking the tunic up and placing it in his lap. He was already within Leonard's quarters; the human's scent engulfed the area, and combined with the moderated temperature, Spock had become drowsy almost against his will, his mind slowing with sluggishness and an overwhelming sense of peace. He could not comprehend why his thoughts remained fixed on the tunic, though. Yes, he could admit – throughout the day, it had soothed him, that much was obvious. He had barely even registered the coldness of the Science Wing over the sense of safety he'd felt with Leonard's scent so close, his presence a constant reassurance at the back of his mind.

But, he was already within Leonard's quarters. He should not still be dwelling on the tunic.

He contemplated this dilemma for approximately 6.39 seconds before deciding that the only way to stop thinking about it was to put it back on. And, admittedly, his fretting seemed to stop almost immediately after the cloth was back around him, snug and comforting. He left the cuffs free to reach his fingertips this time, only pushing them up to rest around his wrists so that he could work on the PADD with minimal difficulty, and he sunk back against the pillows, ordering the lights be turned down to 40 percent.

He soon found himself nodding off despite the early hour and the distinct lack of Leonard's heartbeat against his back. He had gotten so used to falling asleep to the thrumming pound of the human's heart, strong and powerful against his spine, that it was an honest surprise that he'd managed to begin to doze off without Leonard even present. He found it more and more difficult to keep his eyes open as time passed, his eyelids drooping against the brighter translucent glow of the PADD before him until he managed to shake himself awake for the third time in as many minutes, and decided that it would be best to actually let himself sleep. The last time he'd tried to explain to Leonard that Vulcans could go much longer stretches of time without rest than humans, he'd all but been strapped down and forced to get at least some form of sleep for the 7.46 hours they'd been present within his quarters. Admittedly, Spock had been running on 4.8 days of non-stop command on the Bridge after Jim had been in an extended stay in Sickbay for a compound humerus fracture, but that was not the point.

The point was that, after that particular incident, the Vulcan had found it much easier to succumb to exhaustion within the man's quarters than Spock would like to admit. He had also found it much easier to do so when the owner of said quarters was present, although, according to his internal clock, Leonard would not return for at least another 32 minutes. And, there was still work to do – but, it was not urgent. Or at least, did not have to be completed by the end of the day. It could wait for tomorrow, he supposed.

He complied with his lethargy in the end, and shut the PADD off before setting it on the top of the pile of clothing on the bedside table before ordering that the lights be turned off. He shuffled further into the covers, inhaling the relaxing scent of Terran soil and peaches that was imbedded in the sheets and the tunic still wrapped around him, before he finally allowed his mind to relax and drift off into slumber.

When he awoke again, approximately 51 minutes later, it was to a broad figure attempting to climb behind him into the bed without alerting him to their presence. He could already tell it was Leonard; the inherently human emotions that Spock had pushed into a quiet nook at the back of his mind at the beginning of the day, when they had separated to do their duties, where now in full bloom, sheathing him in affection and love and the sharp tang of possessiveness that was only dulled by fatigue. Spock let them flow over him with a noise of content, and Leonard slipped under the blankets with less hesitance than before, taking up the same position behind him from that morning as easily as he breathed. His lips pressed to the back of his neck, and Spock felt any remaining tension drain from him in that moment, sinking pliantly into Leonard's embrace and allowing himself to be tucked in more thoroughly.

"Sorry 'm late," was whispered against his skin, slurred and thick with a tired Southern drawl, and a thumb rubbed against his naval, more pleasant than ticklish. "Mishap in engineerin'. Cost me a few minutes. Y'alright?"

Spock had to work past the sense of relief that had accompanied Leonard's return and had made his already sleep-addled mind that much more lax, but he managed to reply, if hoarsely, "I am well."

Another kiss was pressed to the outer shell of his ear, and Spock shifted away from the touch, if only to make Leonard chuckle under his breath. "Good." Then, he huffed out a sound of amusement and fond surprise, and smoothed his hand over the shirt that covered his torso in almost reverent awe. "You're still wearin' it."

It took Spock a few moments to realize what Leonard was speaking of, but when he did, he felt the tips of his ears warm. "I find your tunic…" He paused. "… adequate. My body temperature remained constant the entire day." When he actually thought about it, the observation seemed startling. There had been very few days where Spock had been completely comfortable for an entire 24 hours on the ship. It was… genuinely surprising, now that it had been brought to his attention.

The human snorted, and tightened his grip around him, locking their legs together beneath the sheets. "Maybe I can convince you t'wear it tomorrow, then." After that, he settled against his back like he belonged there, heartbeat thrumming just at his back, soothing and rhythmic. It easily lulled Spock back into a doze, and after the soft kisses being placed onto his shoulders and throat settled along with Leonard, his breaths deep and long, the Vulcan finally drifted back to sleep.