"Oh, fuck," John swears quietly, throwing his head back to the bed briefly before looking down his body to lock eyes once more. The phrasing should not be sexy, but thanks to Sherlock's deep baritone it immediately makes John's cock twitch.

A flit of doubt trickles into Sherlock's eyes as he reminds him, "Remember, I've never done this before."

John lowers his left hand to Sherlock's curls fondly before replying, "Just be careful with your teeth and I'm sure you'll do fine."

Sherlock huffs at the challenge and lowers his head, ensuring his teeth are tucked behind his lips as he cautiously lets his mouth envelop John's tip. Sherlock's eyes flick up to stare at John, seeking validation and guidance as his hand rests hot and heavy against John's thigh.

"God," John gasps, closing his eyes and licking his lips before cupping Sherlock's chin with his palm, "Stop panicking. You're doing great. Really great."

Sherlock rolls his eyes sullenly before dipping his head again, taking a few more inches into his throat before choking and pulling away. Saliva drips from the corner of Sherlock's mouth which is rapidly wiped away with a scoff of annoyance before Sherlock tries again, taking it much slower and attempting to manage his breathing.

"That's good," John moans, his eyes rolling back, "So good. I hate you for being so quick to pick up new skills," he laughs.

"No you don't," Sherlock mutters around John's cock, making the doctor laugh.

"No, you're right. I don't," John admits, tenderly moving his hand to stroke up Sherlock's cheekbone and then into his dark, messy curls as Sherlock gives a few more tentative pulls on John's cock and lets his tongue explore around the wet slit.

"Do you think you might ejaculate soon?" Sherlock asks, pulling off and looking up innocently at John, "I'm not entirely sure I like the idea of swallowing your semen."

"Er…" John blinks and tilts his head at the oddness of their shared conversation in what is supposed to be an intimate and tender moment, "Not yet no. I'll warn you."

Sherlock nods and bobs his head again, licking and sucking the skin before using his hand to stroke at the soft skin of John's thighs. The sensation is too much, yet not enough as John lets his head fall back and his eyes flutter closed, one hand tangling into the bedding whilst the other strokes through Sherlock's hair, not pulling or holding but merely stroking as a firm presence of their connection.

After a few moments of sloppy sounds and tentative dips of the head, John growls and looks down at Sherlock, using his hand which was in the bedding to tap Sherlock's shoulder, "Lube?" he asks and Sherlock nods hesitantly, nodding towards the bedside table where a brand new unopened bottle lays. John unwraps the plastic from the top and opens it to have a cautious sniff before handing it to Sherlock with an embarrassed smile, "You can...put a finger in? If you want? Only if you want to do that."

"Yes," Sherlock agrees breathily, without a hint of hesitation, and presses a kiss to the inside of John's thigh as he gathers himself up and opens the lid to pour some onto his fingers and warm it up. John's mouth is dry as Sherlock runs his now wet fingers up and down his buttocks and John spreads his legs wider, placing his feet flat on the bed to make it easier for the virgin detective.

"Are you sure?" Sherlock asks nervously, eyes flickering up and down John's tight and flushed body as if reading him.

"Definitely," John nods and gathers Sherlock up for a passionate kiss which momentarily takes their both of their breaths away, "Want it. Want you ."

Sherlock bites his lower lip at the words before placing his index finger lightly against John's hole. John hisses as his hips buck of their own accord at the light touch; it's been so long since anyone has touched him there that he nearly forgot just how good it could feel.

"John?" Sherlock asks, unsure if he was trying to pull away from his touch instead of enjoying it.

John registers the hesitancy and feels Sherlock's finger pull away, so he rushes to reassure him, "No no, it's good. So good. God, more."

Sherlock blushes at the request and returns his finger, firmer this time. Slowly, judging by the resistance coming from John's body, he pushes his entire index finger inside. He can't help his curious mind as he moves the finger to feel John's slick passage from the inside. It's overly smooth, and he's certain that the lube is interfering with him feeling everything properly, but the movements cause John to cry out.

"Oh fuck!" John moans, hips bucking again at the feel of the light, inquisitive movements inside him.

Going on instinct, Sherlock moves his finger back out of John's body slowly, feeling as his large, bony knuckles stretch John's hole a bit more than the rest of his finger. Sherlock gets so lost in the sight, feeling, and sound of the experience that he's almost startled when John speaks a real (fragmented) sentence again instead of moans.

"Add another finger," John instructs with only a hint at begging, looking down his body to watch Sherlock's face.

Sherlock's eyes, locked with John's, widen a bit in shock before he glances fretfully back down to where they are joined, "Are you certain?" He asks as his eyes raise to the other man's once more.

"God, yes. Please," John breathes.

Sherlock gently removes his index finger, allowing his slick middle finger to press tightly against it before moving back to John's body. He watches as he slowly - so slowly and carefully - pushes both digits in before glancing up at John's face to make sure he's okay.

John's head is thrashing back and forth at the torturous pace and the thrill of doing this with this man.

Once they're in as far as they can reach, Sherlock experimentally wiggles his fingers again, feeling the difference now that the stretch is more intense. When he accidentally brushes against a bundle of nerves, John's back arches off the bed as he moans louder than ever before.

Sherlock pulls his fingers all the way out in shock, worried that he's injured John in some way, and stutters out an apology, "John, I'm...I'm so sorry, I didn't mean to hurt you."

"What?" John pants in confusion, not entirely sure why Sherlock has pulled away from him.

"Just then I...I hurt you?" He answers with doubt at the end. He's not sure what just happened.

John giggles, "Hurt me?" John looks down at him and smiles, "Fuck, Sherlock, you just found my prostate."

Sherlock knows about the prostate, has heard about its sexual advantages, and flushes again, "Not pain, then?"

John chuckles again, "Some people struggle to ever find the prostate; leave it to my genius to stumble upon it on accident."

Sherlock just smiles innocently with a shrug of his shoulders, pleased by his sheer luck. The warmth of being referred to as John's genius floods through his body and sends a shiver up his spine at the thought of being claimed by the older man, finally finding someone who wants him.

"Come here," John motions for him to climb back up his body so he can kiss him fiercely. When Sherlock rubs his erection against John's thigh, they both let out a moan as the kiss breaks, "Sherlock," John whispers, swallowing nervously.

"John?" Sherlock questions, pulling away enough to meet his eye.

"I want you to fuck me," he says, trying to sound confident through his embarrassed blush.

"What?" Sherlock asks in complete confusion, like he was just told that 2+2 equals 5 afterall.

"If you want to, I mean…" John rushes to add, "if it's too soon, we can wait but I just…" he trails off, unsure how to continue.

"You want me to penetrate you ?" Sherlock clarifies, still confused.

John laughs self-consciously, bringing his left hand up to scratch through his hair, "Well...yes."

"But…" Sherlock looks less confused, more lost for words. It's a sight John so rarely sees, and he typically likes to revel in the situation. Not this time, "I always thought you'd rather penetrate me ," Sherlock finally finishes his thought honestly.

John's cock gives a pulse in agreement at the thought, "God yes, I want that, too. It's just that, no one has ever...I mean I've never bottomed before, and you've given me so many of your firsts and I have so few to give to you in return. And I want to give you that; I want our first that way to be new for the both of us," he finally brings his rambling to a close, eyes flitting between Sherlock's nervously.

Sherlock lunges down to kiss him hungrily, with far too much force for how close together they are, causing John to grunt at the slight pain before he's moaning again, rubbing his aching erection against Sherlock's thigh.

"You're certain?" Sherlock whispers when he pulls away.

"I'm certain," John confirms with a besotted grin.

Sherlock shimmies down the bed and takes a better position at John's lower end, reslicking his fingers in a haste to get back inside John. His first two fingers slide in easily, his third catches on John's rim and it takes some deep breaths and relaxation techniques from John before even the tips are able to push inside.

"It won't fit," Sherlock panics, his eyes blinking at John's slowly softening penis.

"It will," John says, inhaling deeply and bearing down so that more of Sherlock's digits slip inside. John hums deeply, his eyes fluttering closed as he reaches up to touch and stroke his own nipples, biting hard on his lip, "Let me just...get used to this sensation. It's a bit odd. It burns."

Sherlock nods and moves to kiss John's thigh before using his other hand to stroke John's cock gently, coaxing it back to hardness, "It looked sad like that, growing flaccid."

John giggles and the movement helps Sherlock's fingers slip further inside him until Sherlock's thick knuckles are the only barrier to them being joined completely.

"Move them in and out," John suggests with a groan, "just...stretch me a little."

Sherlock whines low in his throat and feels his cock twitching back to semi-hardness at John's words as he follows orders, creating a slow, sensual rhythm until John is wiggling on the high threadcount sheets in anticipation.

"Oh god," John moans, one hand pinching his nipples whilst the other goes and tangles in his own short hair, "Now. Push them in."

Sherlock hesitates for a split second before pushing in, his knuckles being promptly swallowed by John's hole. Sherlock's hand feels hot, sweat is pouring from Sherlock's forehead as he tries to remain still whilst John gets used to the sensation.

"Yes," John groans, his eyes wide and unfocussed as he looks down at Sherlock, "Oh god. Yes. That's...I'm so full."

Sherlock scissors his fingers, stretching John wider to allow more room for the inevitable penetration. John moans throughout the movements, precome dripping into his pubic hair as his legs twitch and bend, scrabbling at the sheets as his hips buck up and down each time Sherlock brushes against his prostate.

"Now. I'm ready," John insists, he's not entirely sure whether or not he is fully ready, but he can't wait another second before Sherlock's inside him.

"Should I..." Sherlock gestures with his unoccupied hand, "pull out?"

"Yes. Slowly," John says, bearing down to make it easier. He feels Sherlock's hand slip out of him and he feels open and slick but also empty, already missing the fingers.

John watches Sherlock's face as he stares entranced at his open and waiting hole. It makes his stomach flutter to be the cause of such a look on that face. He's still watching as Sherlock shakes his head as though to clear it before he mutters one word.

"Condom," Sherlock states.

John chuckles nervously before agreeing, "Probably best, at least the first time. Do you have any down here?"

Sherlock shakes his head but appears to be thinking.

John pushes himself onto his elbows, preparing to stand, "I have some upstairs in…" but he doesn't get any further in the explanation before Sherlock is using a hand to John's chest to keep John down while simultaneously propelling himself up.

"I'll grab them," he assures and is out the door.

"You don't know where they are!" John yells after him fondly.

"Oh, please," Sherlock scoffs just loud enough for the older man to hear him and is back in mere moments, box of condoms in hand and looking absurdly pleased with himself.

John rolls his eyes with a small shake of his head before reaching out to him, "Come here, then."

The small flame of tender warmth at being wanted alights in his gut once more, and he hurries back to John with all the grace of an over-eager puppy.

There is a tangle of limbs and a slapping of skin as Sherlock positions himself between John's legs again, this time the condom securely between his fingers as he attempts to tear the foil, only to be thwarted by his slippery fingers. Grumbling to himself, Sherlock moves to put the wrapper into his mouth to tear into it with his teeth before John is slapping his thigh and giving him a death glare, "What is the point in using a condom if you're going to put a hole in it with your bloody teeth?" he huffs before holding out his hand demandingly, "Give it here."

Sherlock looks on in challenge before capitulating and handing John the condom with a sarcastic flourish, which amuses John and causes the doctor to roll his eyes as he wipes the excess lube from it and onto the sheets before tearing it easily.

Awkwardness abounds as John wonders whether to hand the condom back to Sherlock or put it on the man himself. Deciding to be proactive, John leans up on his elbows and reaches to stroke Sherlock's cock gently. Pinching the end of the condom, John rolls the sheath down Sherlock's cock with practiced ease (although he's never done it to another person, the mechanisms are the same) slicking up the condom with lube, and then lays back, fluffing up the pillows behind him and then reaching for Sherlock, pulling the younger man down to lay flush against him so they can have tender and gentle snogs whilst they prepare for this monumental moment. Sherlock may not care much about his virginity, but John does; he wants it to be perfect for the man who has saved his life on countless occasions.

John spreads his legs and then wraps them around the back of Sherlock's calves, keeping their legs pressed together as his hand finds Sherlock's cock and places it at his open and wet hole.

"Whenever you're ready you can…" John says, but is immediately stopped in his tracks by Sherlock pushing in with a deep and husky moan, his head moving to John's neck to inhale his sweaty, sex scent, "Fuck. Fuck wait."

Sherlock stiffens and lifts his head, looking down in a panic at John, his eyes flicking from side to side as he reads John's face, "You're hurting."

"Yeah," John admits around a grimace of pain, because it would be stupid to deny what Sherlock can see with his own eyes, "stings a bit."

"Shall I...remove myself?" Sherlock asks, his arms trembling as he holds himself up above John's face.

"No. No just...let me..." John moans, wiggling his hips slightly in an attempt to stop the ache before tensing his internal muscles and shimmying down with a gasp, "Ow you bugger."

"I'll stop. This is stupid. It was a mistake," Sherlock says, intending to pull out, only to be stopped by John's legs which are still holding him steady.

"No, it's fine. It's not so bad now," John half-lies.

"John..." Sherlock whispers, the agony of having to hold still only stopped by his concern for John.

"Okay. No, it's fine…go in a little more. Slowly. As slow as you can," John hums, biting his lip and putting one hand on Sherlock's hip whilst the other slips between their bodies to stroke his own cock which has now seemed to shrivel inside himself, hiding away like a hibernating squirrel.

Sherlock huffs through his nose and slowly begins to slide himself in and out of John's contracting hole, the feeling is exquisite, better than any drug or case he's ever taken. John is hot, clenching and gripping at him as he slips further in, a millimetre at a time.

John's hands grip tighter as the pain ebbs, grasping his hardening cock and surely bruising Sherlock's hip at the same time. Sherlock gasps at the increased pressure, surprised by the wave of arousal that moves directly to his own cock, still trying to move as gently as possible inside of John.

"Sherlock," John gasps, part moan and part call.

Sherlock finds that he needs to open his eyes to look at the exquisite man below him. He has no recollection of closing them in the first place. He searches John's face: open and caring and awed and just a tiny glimpse of pain in there still.

"You remember that spot you found on accident with your fingers?" John asks coyly, hoping that the stimulation will make this experience perfect at last.

"Your prostate?" Sherlock asks with a wrinkled brow before understanding dawns, "Yes! Your prostate!" He exclaims gleefully.

John watches with a fond smile as Sherlock freezes all movement as he tries to work the calculation in his head. Sherlock pulls himself back before giving an experimental thrust back into John's willing body. Both men are watching the other, so John merely grunts and shakes his head, letting Sherlock know that wasn't quite it. Sherlock purses his lips with a small huff, recalculates, and tries again.

This time, John pants and briefly closes his eyes as he bites his bottom lip, "Closer," he assures Sherlock when their eyes have locked again.

With a quick, determined nod of his head, Sherlock pulls back and aims once more. This time, Sherlock knows he's found it because John's back arches off the bed as he lets out a loud moan, his inner muscles squeezing Sherlock's cock in such way that it's almost too much for the detective to bear.

John huffs a laugh in wonder, falling back to the bed to smile up at Sherlock. He moves his right hand from Sherlock's hip to the back of his neck, pulling him down for a passionate kiss, "You bloody genius," he mutters against his lips, placing another kiss before continuing, "God, you're wonderful."

Sherlock's hips stutter forward of their own accord as he moans out a, "Joooohn."

"Yes. God, please, Sherlock!" John begs, all intentions of having a slow, sensual love-making session now blown wide open at the sensations. He needs it hard, fast, and passionate.

Sherlock's hips judder into movement, making long thrusts as Sherlock's sweat drip, drip, drips onto John's torso. John is biting his lip, almost broken by the intensity of his need to be claimed by Sherlock. His legs wrap around the detective's waist and it's the perfect position for Sherlock's blunt tip to pound against his prostate again and again, coaxing floods of precome out to drip along John's stomach in thick rivers.

"Sher...Sherlo...I can't," John's whining, his voice high pitched and strained as his hands slip and grasp for the younger man's shoulders, "I can't hold on. I'm going to...going to..."

"John!" Sherlock gasps, eyes flying open to gaze at John in amazement as his orgasm hits him, spurred on by the twitching and grasping muscles of John's insides. Sherlock makes a few more choking noises as his cock pulses inside the condom, leaving Sherlock feeling wrung out and strangely emotional as he smoothes back his damp curls with his forearm.

Pushing Sherlock up, John can finally reach for his cock, which hasn't abated in its desperation. He's red tipped and straining, hot to the touch and leaking almost worryingly compared to his usual dribbles. John reaches up, holding the back of Sherlock's neck to pull him down so they can rest their foreheads together, sharing breath as John strokes his cock harder and faster, getting to the edge and then...

"Oh," John moans out simply, his eyes rolling back as he comes hard, soaking his and Sherlock's chests and stomachs with long arcs of ejaculate as he shudders and trembles under the detective.

"John," Sherlock blinks, looking down between John's face and still pulsing penis, "John…oh, John."

"I'm alright," John mumbles, taking a deep, hissed breath in and smiling, "I'm...I'm fine."

"I could feel you," Sherlock rambles, blinking continuously, "I could feel you coming, around my penis. You were tensing."

"Yeah," John laughs, "Internal muscles. That's how orgasms work."

"I know that," Sherlock scoffs, rather haughtily for a man still buried inside his lover whilst wearing a sperm-filled condom, "I'm not an imbecile. I just meant that...I could feel yours. It was like we were…"

"Connected," John finishes, smiling warmly and then cupping Sherlock's cheek with a wince as his rear starts to ache, "You need to pull out now, love, sorry."

"Oh. Oh of course," Sherlock says formally and looks a little lost for a moment.

"Hold the condom base, then pull out," John instructs with a stroking of Sherlock's cheekbone, "dispose of the condom in the bathroom bin."

"Dispose?" Sherlock frowns, "Why would I want to do that?"

Nevertheless, Sherlock pulls out with only the briefest wince from John and then sits back on his heels. Sherlock's cock is growing flaccid, the now (substantially) full condom at danger of slipping off and onto the bed.

"You can't keep it," John sighs affectionately, rubbing his face and grimacing at the smell of semen on his fingers, "What do you want to do? Keep it as a pet? Name it Bernard?"

Sherlock looks at John like he has gone clinically insane before shaking his head, "Experiment."

John should really have seen that coming. He pushes himself to sitting while laughing, pulling Sherlock's face to his for another kiss.

"Oh, I keep forgetting you're a scientific genius," he chides with a besotted smile.

Sherlock smiles as he rubs his nose softly against John's, his stomach warming again, before whispering, "Yours."

"Hmm?" John asks, frowning softly, "What was that?"

"I said yours. I'm your scientific genius." Sherlock blushes, obviously shy.

John takes a moment to gaze up at his best friend, flatmate, work colleague, and now lover. The man who had changed everything the moment they met in a lab which smelt so strongly of formaldehyde. He had never expected he could be here, loving Sherlock and feeling the love returned.

Fighting back tears, John can see Sherlock is excited to begin his experiment and rolls his eyes playfully. Kissing him once more before slapping Sherlock's arse lightly, John sighs, "Alright, off you go before the sample is unusable and we have to make another one."

Sherlock stands with a smile, shimmies back into his pajama bottoms, and make his way to his lab, all while thinking that John's idea holds a lot of merit.

A/N: As always, I would love to hear your thoughts via comment or constructive criticism!

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