Days slowly lead into weeks, Sherlock seemingly forgetting all about the events of that night while John replays them on repeat in his head. In that quick moment of Sherlock climbing off of John's lap and walking away, it seemed to mark the end of Sherlock's little experiment, never bringing it up, never attempting to progress it, as if it never happened in the first place.

John finds himself vividly replaying the many instances of watching Sherlock on his knees in front of him, can almost feel the suction of the detective's lips on his cock and he can't help but feel his erection springing to life. It happens only at night as he lay in bed, attempting to wind down from a busy day at the surgery, only to find himself palming his erection and using the images of Sherlock sucking him off as fodder for his masturbatory activities. Many times he tries to concentrate on other sounds coming from the apartment, from Sherlock's room below his, but just as he's never once seen Sherlock give any attention to his own erection, he's never capable of hearing the sound of the detective masturbating either.

The thought gives John an idea, and he feels his nerves firing on all ends as he releases his erection from his hand, pulling his pajama bottoms off as he slides off the bed and walks over to the door, completely nude.

The flat is silent, not uncommon for two am, but as John quietly makes his way down the stairs from his room, he hears a faint sound coming from the kitchen, followed by a quiet, frustrated sigh. When he peeks around the corner, he finds Sherlock sitting behind his microscope, his eyes closed as he rubs at his temples, clearly frustrated at whatever experiment he's working on.

Without saying anything, John slips from around the corner, making no attempts at being quiet when he walks past the detective into the living room, feeling eyes suddenly on his back as he makes his way to his chair, giving no attention to Sherlock as he sits down, his erection standing proud, the pre-cum glistening on the head.

John counts silently in his head, waiting for Sherlock to acknowledge him as he stares blankly at the empty chair across from him "3…2…1…"

"What are you doing?" Sherlock's voice is quiet, inquisitive, and John can almost visualize the look of intrigue on the detective's face as he debates whether or not to approach the naked doctor. Perhaps Sherlock thinks he's sleepwalking.

When John doesn't answer, Sherlock finds himself walking slowly into the sitting room, almost in a predatory fashion, looking at the blogger from head to toe, taking in the sight of the hard cock his mouth has been watering for. He wants to sink between John's spread legs, consume every centimeter of him, but the logical part of his brain is very much on guard at the moment and reminding him of the events that occurred last time.

"John-"

"Sit."

The commanding tone in John's voice sends jolts straight to Sherlock's own cock, hesitating for only a split second before he finds himself sitting in his chair, John looking directly at him, almost in a curious way.

"I want to see you masturbate."

With those few words, Sherlock finds his whole body stiffening up, his breath catching in his throat, and he can almost feel the beginnings of his erection starting to wilt within his pajamas, his palms suddenly getting sweaty as they rest on the arms of the chair.

"John, we both know this was a failed experiment."

"Then I'm proposing a new experiment, to settle it once and for all. I want to watch you masturbate, if nothing happens, then we know we're both right."

The room is silent as Sherlock contemplates the proposal, his eyes taking in every bit of the naked man sitting across from him as he can, feeling himself stiffening at the site of the doctor's erection. He closes his eyes as he tries to force himself to relax, listening to the sounds of his inhales and exhales, rubbing the sweat from his palms onto the armrest of the chair.

When he opens them again, John is very much focused on his movements, Sherlock attempting to figure out what the blogger is thinking but failing miserably. He already knows how this little proposed experiment with John 'not gay' Watson is going to end, with him standing over the sink in the bathroom, hand fisting his own erection, trying to ignore the look on John's face when he realized he was-

Sherlock's thoughts stop with a sudden jolt, his eyes snapping open when he feels the fingers on his skin, gently touching the area above the waistband of his pajama bottoms. He doesn't realize he's stopped breathing, his mind getting fuzzy around the edges as John hooks his fingers in the waistband, Sherlock's hips lifting up automatically as his legs are exposed to the cool air.

"Masturbate."

Sherlock finally releases the air he's been holding in as he feels a moan escape from deep within his throat, watching John sink to his knees in front of him, just out of his reach so that they're not making any contact. It's hardly comforting, but Sherlock's body makes it evident that it cares very little as his erection twitches, his hips shifting slightly upwards as he closes his eyes again and wraps his hand around the base of his hardened cock, trying to forget the eyes that are currently on him.

Other than the one incident of Mycroft walking in on him when he was younger, Sherlock has never masturbated while anyone watched, let alone sat so close to him that he could feel the light ghosting of John's breath on his inner thigh. As he allows his hand to glide up to the head, thumbing the slit, Sherlock can only fleetingly wonder what caused John to want to see this, knowing his affinity to denying his closeted sexuality.

The thought is gone before he can ponder it, however, as his hips buck up violently and he feels a hand close over his, his breaths coming out in short gasps as he lets his eyes slide open, taking in the focus on John's face as he leans forward, concentrating on his movements as he takes over the rhythm of strokes, speeding up Sherlock's hand.

The erection hanging between John's legs isn't exactly as swollen as when he initially walked in, but it is definitely still present as Sherlock unconsciously slides himself forward in the chair, noticing John's lack of movement as the detective's cock stops just short of his face.

For a moment it feels like a stand-off, their hands stopping, John's breath catching in his throat as he stares at the impressive erection in front of him, one hand covering Sherlock's while the other rests on the detective's thigh. For a split second Sherlock thinks that John is going to close the gap between lips and cock, but he quickly realizes John is locked in a battle with himself as his hand loosens from Sherlock's cock, the other dropping from his thigh.

The tension suddenly pours from John's body, and Sherlock finds himself sighing dramatically as he pushes John's hand away from his, the blogger looking confused and slightly panicked as he's pulled to his feet and pushed backwards, almost faltering but instead landing in his chair behind him.

Without a word, Sherlock straddles John's hips, their erections rubbing together and causing John to let out a quit gasp, his hands grabbing the arms of the chair as he stares up at the man in his lap. He opens his mouth to say something, anything, but Sherlock ignores it as he leans forward, capturing John in a heated kiss as his hands slide down the bloggers arms, stopping at his hands as he pulls them from the arm rest and places one on his ass, the other coming between their bodies as Sherlock pulls away from the kiss.

"Sherlock." The word comes out in a strangled gasp as John suddenly finds two of his fingers enclosed in the warmth and wetness of Sherlock's mouth, the detective's tongue coating the digits in a thick layer of saliva before he pulls them out and pushes his hand between their bodies, bollocks brushing against his hand as Sherlock releases his grip with John's fingers just at his tight entrance.

The ball is in John's court, his chest tightening and his respirations stopping as he closes his eyes. He feels the saliva on his fingers drying and knows he has to make a quick decision on what to do, but then he feels Sherlock grabbing both of their erections together in one hand and he finds himself unconsciously thrusting his fingers up, a pleased sound coming from Sherlock as John finally lets his eyes slip open.

His fingers are buried deep within Sherlock, the detective's eyes closed and lips slightly parted as he grabs John's shoulder with his free hand, the grip tight enough to leave a mark as he slowly pulls up and then forces himself back down, the motion slow but more than pleasurable for both men.

There's far from any question on John's enjoyment in the activity as Sherlock begins to stroke their cocks together, John's head falling back against the chair as he watches Sherlock over him, revels in the feel of the tightness of his fingers, tighter than any woman he's felt before.

The thought makes his cock twitch in Sherlock's hand, and the blogger removes his fingers only to replace them with a third with no prompting, a bead of sweat sliding down the ridges of Sherlock's spine before slipping between his crack and landing on John's hand.

John considers the times he's had a woman in his lap, his fingers inside them, stretching them before they lowered themselves onto his impressive cock, but this is very much different as he watches Sherlock, sweat beading across both of their brows as the detective's eyes remain closed, concentrating, small puffs of air coming out with each thrust down onto John's fingers.

The grip on Sherlock's ass lessens as John slides it around his waist, watching the detective's eyes slip open as the touch moves up his chest and around his neck, the bloggers grip firm as he pulls Sherlock towards him and their lips meet in a messy collision of tongues and pornographic moans.

After a moment Sherlock pulls away, his chest heaving as he drops his head, John wondering what he's doing only for a second before he feels the wetness of Sherlock's spit on his erection, the detective removing his own cock from his hand before focusing solely on John's, spreading the saliva down the shaft before pulling himself up off the blogger's fingers, repositioning himself so John's thick head twitches against his entrance.

This time Sherlock doesn't wait for John to make the move, lowering himself until he's filled to the hilt, his eyes finally meeting John's as the blogger lets his head fall back again. His hands rest on Sherlock's thighs, thumbs splayed wide as they press into the crease of the detective's groin, his rapid pulse present in the femoral arteries that lay just below the blogger's thumbs.

The movement is clumsy at first as they try to find their rhythm, Sherlock gripping the head of the chair on either side of John's head as he rides his cock, their moans and grunts surely audible in Mrs. Hudson's flat. He tries to duck his head down to capture John's lips, but their movements are too frantic, too concentrated on the pleasure as Sherlock feels a hand suddenly wrap around his erection, stroking in time with the thrusts, foreheads pressed against each other as eyes remain closed.

It doesn't take long before both of their bodies are shuddering with pleasure, John's hand becoming coated in Sherlock's semen as the detective feels the blogger's cock pulsating within him, cum following the softening prick as he pulls out of Sherlock and grabs his ass firmly with both hands, pulling their bodies together as their lips finally meet again.

Its several minutes before they're able to get their breathing under control again, their pulse rates slow to come down as Sherlock sits back in John's lap.

"I think the experiment was inconclusive." John looks confused by Sherlock's words for only a moment before a wide grin spreads across his face, understanding setting in.

"I think you're right, perhaps we should change the variables slightly. Your bed or mine?"

And they fucked happily ever after. The end.