VULCAN BIOLOGY

Jim sighed as his lips slid against Spock's. The pair lay on their sides on Spock's bed, caressing one another through their uniforms. Jim inched his body closer; he always savored every touch the reserved Vulcan allowed him. They had been in a romantic relationship for roughly three months. They kissed, of course, both in the human and Vulcan ways, even made out and lightly petted one another in secluded corners of the ship, but this was the first time Spock had permitted him into his bed.

A soft moan vibrated in Jim's throat when Spock's knee brushed against his groin. His pulse quickened. He felt Spock's hands gliding across his back, one occasionally venturing up to play with the short hairs at the base of his neck. He loved Spock's hands. His long, nimble fingers. The soft palms. How they could so skillfully execute a nerve pinch, but turn gentle a moment later.

Jim pulled back to catch his breath, resting his head mere inches away from Spock's. He could not help the tender smile the Vulcan brought to his face. Warm breaths escaped Spock's pink lips, parted slightly from exertion. His deep, brown eyes swam with - could that be happiness peeking through? Jim brought his hand up and caressed the side of Spock's face, stroking his thumb along the sharp cheekbone.

"Is this alright, Spock? Are you comfortable with this?"

"I am," said Spock softly. "I've never been this close with anyone. Romantically or physically."

"How does it make you feel?" Jim asked, his lips a hairs breadth away from Spock's.

"I feel...warm. My heart rate has increased by 12.3%, my blood pressure by 9.5%, and there is increased blood flow to the lower parts of my body."

Jim's eyebrows shot towards his hairline. "So in other words...you're turned on?"

Spock thought for a second. "I believe that is the human vernacular."

A flood of excitement rushed through Jim's body, though he did his best to contain it. "Would you like to take things further?" He let his hand wander down Spock's side, feeling his ribs expanding through his uniform.

"I think...that, indeed, would be pleasurable."

Jim bit his bottom lip and started to close the gap between them, but stopped himself. He suddenly remembered something. "You know, I've been reading up on Vulcan physiology, purely out of curiosity, and the text mentioned that Vulcan genitals differ quite a bit from humans', but it didn't go into much detail. Just...howdifferent are they?"

Spock quirked one of his eyebrows. Jim could have sworn he saw him trying to suppress a smile. "Would you like to see for yourself?"

Jim's breath caught in his throat. "S-sure."

Spock's eyes lingered on Jim's for a second before he turned and sat on the edge of the bed to remove his boots. Then he stood, facing Jim, and pulled off his blue Starfleet shirt. He carefully folded it and placed it on the ledge behind the bed.

Jim watched him, his heart racing, rushing the blood to his groin. From neck to waist, Spock looked like any other human male. Jim knew this; he had seen Spock shirtless before, but he still enjoyed what he saw. Lean muscles rippled under pale skin. Dark hair covered his chest. A narrow trail disappeared into his pants...

Spock undid the fastenings on his pants, slipped his thumbs into them, and slowly pushed them down and off his hips. Jim's eyes widened slightly. Instead of what he was used to seeing when he looked in the mirror, between Spock's legs rested two smooth, parallel folds of skin. At first glance, they appeared to be the same color as the rest of Spock's skin, but the longer Jim looked, the more he noticed an almost imperceptibly subtle greenish tint.

After he had neatly folded his pants and placed them next to his shirt, Spock crawled back into bed and lay on his side just like before. His hand came up to caress one of Jim's soft, muscled pecs.

"As you can see, my reproductive organs are internal. The testes remain so all of the time, and, in its flaccid state, so does the phallus. When aroused, it emerges, erect," Spock explained as casually as though he were discussing the weather, but at the same time one of his thumbs brushed Jim's nipple through his shirt, causing him to gasp.

With Spock laying naked next to him, Jim suddenly became aware of how many clothes he was wearing. With an undignified whine, he wrestled himself free of his command-gold shirt, ruffling his hair just enough for some of it to fall over his forehead.

"Much better," he murmured before pressing his lips against Spock's.

Lacing one arm around his back, he pulled Spock close against him, slipping one knee between his legs. Spock let out a tiny moan and Jim felt him rub his folds against his thigh. To encourage him, he moaned back and trailed little kisses across his cheek and jawline.

"Can I touch you?" he whispered.

The corner of his mouth twitching, Spock took his hand and guided it to his folds, pressing it lightly against them. Jim marveled at how soft they were, how smooth. Spock shifted his hips against both their hands, biting his lip to suppress a moan. Studying Spock's face closely, Jim rubbed the folds a little harder. He let out a sigh through his nose and closed his eyes. Spock's hand traveled up Jim's arm to his strong bicep as he continued with this gentle stimulation; he seemed to be catching on quickly.

Jim traced his fingertips around the outsides of the folds, brushed them along their tops, applied varying degrees of pressure, all to Spock's apparent approval. His moans became increasingly louder with every passing moment.

"That's it, darling...let me hear you," Jim whispered into Spock's graceful, pointed ear.

Spock shuddered and his grip on Jim's arm tightened. Jim felt him rock his hips into his hand, yearning for more contact. He wondered what lay beneath those exquisite folds, what biological wonders were tucked inside. Did he dare venture further? No, not yet. He didn't want to make Spock uncomfortable. This was the most intimate contact they had shared as of yet, and he realized how much trust Spock had to have placed in him to allow such a thing.

As Jim continued to gently stimulate him, Spock released his arm and curled that hand around the back of his neck. He pulled him close and kissed him, heated and hungry. He moaned into Jim's mouth and ran his fingers through his honey-colored hair. Oh gods, it even smelled like honey. Spock knew Jim favored his own more expensive shampoo over the bland Starfleet-issue toiletries that came with their job; he had just never paid attention to how wonderful it smelled. The scent of his hair, his human skin, the feeling of his gently probing fingers all threatened to make Spock come undone right there.

Jim drank in every moan Spock made as though it were water in a desert. His cock swelled in his pants where it pressed against Spock's thigh. With one particular thrust of Spock's hips, his finger accidentally slipped between the folds just a bit and he felt something wet. His curiosity getting the better of him, Jim carefully parted the folds and let two fingers slide between them. Spock gasped and tensed. His eyes flew open.

"Is this alright?" Jim asked softly.

"Yes," Spock breathed.

Jim pushed his fingers deeper and was met by a narrow but flexible cavity, warm and wet to the touch. He was surprised by how much warmer it felt than Spock's outer skin. And the wetness was like a slick mucus. It felt like - well, almost like a vagina.

Jim explored this new part of Spock's body, scissoring his fingers, gently massaging the walls which contracted around them. Spock's eyes fluttered shut. He clung to Jim, gasping.

Jim kissed his lips, then his cheek, then his neck. "Mhm, Spock...you're so wet. That's a good thing, I hope?"

"Yes." He buried his face in Jim's shoulder. "Go deeper."

Cautiously, Jim did so, listening for any sound that might indicate Spock was in pain. Only when his fingers were buried up to the knuckle did he feel a wide, soft mound hidden within his body.

"Is this -"

"That is the head," said Spock.

Grinning against Spock's neck, Jim said, "Well, why don't I see if I can coax it out?"

He kissed the area right below Spock's ear and circled his fingertips around that mound of flesh, receiving a desperate moan in return. He pressed and massaged, and when he detected a small deviation that must be the slit, he brushed one finger across it. The head in turn pushed back against him. It was working.

"Jim! Yes! Ah - that's good!" Spock rasped.

Jim had never seen him like this before, so desperate for touch, so utterly stripped of his composure. It made his own cock twitch within its confines. As Spock's cock slowly began to emerge, Jim felt it growing harder, more persistent. Soon there was no room left in Spock's body for his fingers. Jim watched as the dark emerald length emerged, glistening, making a wet sound as it appeared.

"Spock, you're beautiful," he said, raking his eyes up and down his lithe Vulcan body, from his cock to the tips of his ears, which were beginning to blush green themselves. Jim wondered why he blushed - had no one ever said such things to Spock? Never told him he was beautiful? Jim intended to prove it to him.

Wrapping his hand around Spock's length, Jim sealed their lips together and began to stroke him, the mucus providing an excellent lubrication. Spock's hips jerked. He moaned; his entire body trembled under Jim's touch. His expert hand worked him up and down, applying just the right amount of pressure, flicking his wrist at just the right moments. He wondered how often Jim did this to himself...and if he ever thought about him while he was doing it.

Jim parted their kiss, but only a little, and touched his forehead to Spock's. "Yes, Spock. I do think about you when I touch myself," he whispered.

Spock's eyebrow perked up; perhaps their bond was stronger than he initially thought.

Jim continued. "I think about you every time. When I see you bent over your science station, I think about the things I would like to do to you..." He thumbed the slit and Spock grunted. "Do you ever think of me, Spock?"

"Y-yes, I do. Quite often," Spock's voice came out strained.

"What do you think about me doing? Would you like to try any of those things right now?"

Spock thought he might fall off the bed if it weren't for Jim's hands holding him there. So many images flashed before his eyes: Jim taking him in various positions, in scandalous places around the ship...in a hidden corner of the engine room, across Spock's desk in the laboratory, the showers at the gym; in the arboretum, sheltered behind the bushes and surrounded by the perfume of all the flowers... Spock hoped not all of these bled through their bond just yet. But there was one particular image that kept peeking through above the rest.

"Will you...put it in your mouth?" He asked quietly, a green blush flooding across his cheeks.

Jim narrowed his eyes and smiled. "Why, Mr. Spock...you're naughtier than I thought you would be." He kissed him lightly on the lips and shifted their bodies so Spock was flat on his back and he straddled his thighs. He kissed his way down his body, taking a few moments to bite and suck at his nipples. Jim's cock now strained against his pants, growing more and more uncomfortable with every delicious moan that escaped Spock's kiss-swollen lips.

Jim kissed along the sharp planes of his hips, moving in an ever tightening circle around the glistening length between his legs. The closer he got to it, the more he noticed an alluring, musky scent; it must be something in his natural lubrication. Glancing up at Spock, who had propped himself on his elbows to watch, he let his mouth hang open a bit and licked a slow line up the underside of his cock. Spock shuddered and gasped. His head fell back and his eyes fluttered shut.

Holding him steady at the base, Jim circled his tongue experimentally around the head, nearly driven insane by the scent and the taste, unlike anything he had ever experienced.

"Oh, Jim...Jim!" He loved the way Spock moaned his name and squirmed under his touch.

Spock cried out softly as Jim's lips closed around the head and he slowly pushed more of it into his mouth. He forced his eyes open. He had to see this. Jim still watched him closely. Such an attentive lover. He took Spock about halfway down before he began to slowly bob his head, using his hand to stroke along the rest.

"Jim! Oh my god!"

Jim knew he must be doing something right to make Spock appeal to a deity. He sucked and lapped at the copious amounts of lubrication that continuously flooded his mouth. Spock's hips rutted up against him in tiny, controlled thrusts. He continued to moan louder and louder. Jim grazed his teeth along the hardened flesh, earning him a cry that anyone else might mistake for pain, but he knew otherwise by the way Spock's hips quivered and the way he fisted the sheets.

With his curiosity mounting again, Jim swiftly took the rest of Spock into his mouth, but this time that curiosity backfired. Spock's hips jerked upward involuntarily, ramming his cock down the back of Jim's throat. He pulled off him, choking and clutching at his throat.

"Jim! I'm so sorry! Did I hurt you?" Spock shot up and grabbed his shoulders.

Jim coughed once more, tears forming at the corners of his eyes. "I'm fine. I promise. I just wasn't expecting that." His voice came out a little raspy.

"Neither was I." Spock stroked his lover's shoulders while he drew in a few deep breaths. "Are you certain you're alright? I understand if you do not wish to continue."

"No, I want to. Let's just...be a little more careful."

Spock nodded and let himself be pushed back onto the bed. Jim straddled his legs again, leaning down so he was eye level with Spock's emerald green cock. But this time, he used both of his hands to hold Spock's hips in place.

"You can thrust if you need to, just be easy," he said.

Spock swallowed and gave a small nod, forcing his mind to clear enough to assert control over his aroused body. He stayed propped on his elbows and watched as Jim carefully pushed his mouth down onto his cock. He took him all the way down again, casting him a confirmatory glance.

Spock felt almost dizzy at the sight of Jim with his cock sheathed inside his mouth, his lips forming so perfectly around it, his hair falling over his forehead in such an attractive manner. Jim slowly began to move, creating a gentle suction with his lips that caused Spock to moan low in his chest. He spread his legs slightly to give Jim better access, and only when he felt Jim press his crotch against his thigh did he realize just how turned on he was by all this. Jim was rock hard against him, rolling his hips to gain some much needed friction. The blond moaned around him, sending tiny vibrations all through his body.

The longer he went, the more Jim wanted - needed - something more, something different. He needed to feel Spock inside him. Only, he had never done anything like this, and he was willing to bet Spock hadn't, either. He knew Spock would never hurt him intentionally, but what if they had another...accident like before? Perhaps if he was on top, he could set the pace easier.

Pulling off of Spock with an erotic pop, he panted and stroked him painstakingly slowly. "Spock...can I ride you?"

Spock looked at him wide-eyed for a moment, as though something had short circuited in his brain. He swallowed hard and said, "Yes...please, Jim."

Trembling with anticipation, Jim got off the bed and stripped himself of his boots, socks, pants, and underwear, carelessly tossing them all to the floor. He climbed back on top of Spock, pausing when he noticed a slightly dismayed look on the Vulcan's face.

"I don't have anything to prepare you with," he said.

One corner of Jim's mouth curled upward. "Oh, yes, you do."

He wrapped his hand around Spock's cock and coated his fingers with the thick lubrication gathered there. Bracing one hand against the bed at Spock's side, he reached back and brushed his fingers against his own tight opening. He carefully slipped one inside, tensing around it. Spock's hands came to rest on his thighs and stroked them to help him relax. Jim gasped as he worked the finger in and out, getting used to the feeling. His body arched, causing his aching cock to brush against Spock's. They both sighed and shifted against one another.

Spock secretly marveled over Jim's human anatomy. His thick cock arched directly from his body with no folds to retreat into, pinkish in color and leaking precum from the tip. And his testicles hung outside his body, not protected and internal the way Spock's were. Humans really were such unusual creatures.

Jim's eyes closed and his mouth fell open as he added another finger to his body. Spock's cock twitched at the sight. "Jim...can I touch you?" he asked.

Jim nodded frantically. Spock gathered both their cocks in his hand, covering them with his own lubrication.

"Oh, Spock..." Jim sighed. His hips spasmed, not knowing whether to thrust into Spock's hand or back onto his own fingers. He soon found a rhythm he liked and almost lost himself in the sensations. Oh, it was so perfect.

Sensing his lover beginning to relax, Spock released their cocks and lifted Jim's body slightly. "Jim, let me help." He reached between his legs and carefully inserted two fingers of his own, alongside Jim's two.

"Oh, fuck!" Jim cried out.

For a split second, Spock worried he had done something wrong again, but the way Jim thrust down onto their fingers told him all he needed to know. Working together, they gently stretched him open. Spock especially enjoyed the feeling of Jim's tight, warm body clenching around his sensitive fingers. His first two fingers. A devilish thought suddenly came to mind.

"I bet you never thought you would receive an internal Vulcan kiss, did you?" Spock curled his fingers forward against Jim's prostate, almost making him collapse.

"Spock! Oh, fuck! Are you - sure you've - never done this - before?" Jim asked between gasps for air.

Spock gave him one of those tiny smiles he reserved only for him. "Quite sure."

It took only a couple more well placed thrusts for Jim to know he was ready. A tiny, involuntary whine escaped his lips when their fingers left his body. He climbed further up Spock's body, hovering over his cock. He reached between them and lined it up with his opening. Spock's hands appeared on his hips again, squeezing them gently. The two of them locked eyes as Jim slowly began to lower himself down. He curled his lips around his teeth as Spock stretched him, filled him, reaching depths their fingers could never hope to.

As he settled in Spock's lap, he tensed and made a little "ah!" sound as a dull pain sprang from deep within his body. Spock's hands traveled from his hips, up his sides, soothing him.

"Relax, t'hy'la. There's no rush," he assured him.

A bead of sweat rolled down the middle of Jim's back as he concentrated on opening up his body. Gradually, the pain began to lessen, helped by Spock's wandering hands. Carefully, Jim raised himself up so that only the head remained inside him, then eased himself back down. A rush of air escaped his lungs as he did, and Spock moaned low in his throat. He repeated this motion, a bit faster.

"Jim! You're so tight...so warm."

"Do you like it?" Jim asked, lifting and lowering his body a little faster.

"Yes!" Spock gasped.

Finally getting used to the feeling of Spock's cock inside him, Jim began to ride him in earnest. He placed his hands on either side of Spock's head for support.

Spock grunted. "Ngh, Jim! Can I thrust now?"

Jim leaned close to his ear. "Give me everything you've got."

The look that came over Spock's face sent shivers down his spine. Strong Vulcan hands grabbed onto his hips, and that thick length was driven into him over and over. Jim cried out desperately as he moved to meet Spock's every thrust. He wrapped his hand around his own cock and stroked himself to match their pace. In the excitement, their movements came across somewhat clumsy at first, but they soon figured out what the other liked, what brought about the most pleasure.

Jim forced his eyes to remain open; he didn't want to miss a second of this. His cock twitched at the sight of Spock in the throws of ecstasy. The ecstasy he was causing. He drank in every detail: the way his brow furrowed, the way his eyes clamped shut, the desperate moans and cries spilling from his parted lips. Jim clenched his muscles around Spock, and the Vulcan's eyes flew open. Those chocolate brown orbs burned with desire.

Jim swooped down and sealed their lips together, thrusting his tongue into Spock's mouth. He tasted faintly of the plomeek soup he had had for dinner. Spock seemed a bit startled by the sudden intrusion, but moaned around it, bringing his hands around to his back. He dug his nails into the soft flesh.

Jim groaned, pulling back a bit. "That's it, Spock. Mark me. Make me yours!"

Spock pulled him down and sank his teeth into his neck, not hard enough to break the skin, but enough to make Jim cry out and thrust hard onto him. The pain mixed so perfectly with the intense pleasure coursing though his body like molten lava. Jim's arms felt weak by the time Spock's teeth released him.

"Jim! I'm close! I need - ah! There is something -"

"What do you need?" Jim asked, hovering over him.

"May I - ejaculate - inside you?" Spock panted.

Jim saw the desperation in his eyes, the fire in his blood. He would have liked nothing more than to feel some of that fire inside him.

"Of course...t'hy'la."

The sound of Jim's voice forming that Vulcan word was all Spock needed. He grabbed onto the man's hips and drove his cock into him once more. He came with a shout, throwing his head back against the bed. Wave after wave of pleasure crashed over him, drowning him.

Jim's hips shuddered as Spock filled his body with copious amounts of hot cum, far more than what the average human produced at one time. He clenched around him, happy to receive every bit of it. He continued to ride Spock throughout his orgasm, and soon, let out a cry of his own as he came all over Spock's abdomen. His hand spasmed around himself, gradually dissolving into long, slow strokes, squeezing out every last bit he could manage.

Finally his arms gave out and he collapsed on top of Spock, grimacing a little as his cum squished between their bodies. Spock didn't seem to mind, though, as he was immediately enveloped by those strong Vulcan arms. For several minutes, neither said anything. They simply enjoyed the closeness of their bodies, the intimate contact they still shared. Jim sensed an almost overwhelming feeling of love and tenderness being pushed across their newly established bond. He buried his face in Spock's neck and tried to return those same feelings as best he could; he wanted Spock to know how much he cherished him.

Spock allowed his eyes to drift shut and he nuzzled Jim's hair. Their chests moved in perfect sync as they fought for each ragged breath. He was content to stay like this, holding Jim, feeling his heart thudding against his chest, caressing his slim, soft body for hours. Their respective shifts were over. They had no pressing responsibilities. Just each other.