Apparently it's national kissing day. Here is my tribute to that fact.

Sherlock narrows his eyes, squinting across the flat at one John Watson. He's reading the paper, but it's clearly nothing exciting – there's a harsh frown creasing his forehead as his eyes dart back and forth over the little black letters. He seems to give up, setting the paper down, sighing, and leaning back into the chair. He doesn't notice Sherlock's stare, which the detective sees as particularly unobservant: it wasn't like he was trying to hide the fact.

He continues to watch the doctor for about a minute longer, before returning to his experiment. People were so enclosed in their own little worlds that they never for a second bothered to really look.

It's approximately 28 minutes later that John joins him in the kitchen, yawning and making his way over to the kettle.

"Coffee please, John," Sherlock requests, not bothering to look up from his experiment. So far, it's been extremely informative: he's discovered the effect of several different acids on several different tissues. After that last case, he's inclined to wish that he'd experimented similarly beforehand. It's unlikely that a similar case will crop up again in quick succession, but he is not willing to be unprepared twice. He'd had to make do with estimates, which had thankfully been right. Nonetheless, he is uncomfortable with the uncertain.

His eyes locked on the fingernails in front of him – cataloguing the way in which they dissolve, and the remnants left behind – he hears John muttering to himself, something about not actually offering him anything. It was clear he was about to, why wait for him to actually form the words?

Yes, John – manners. Dull.

By the time the nails in front of him reach a stable state, John has finished preparing the beverages, and is holding Sherlock's coffee out to him, leaning against the counter in a manner that suggested he was going to stay there. His eyes keep darting to the experiment; his mouth twitching slightly – as if he wanted to ask what Sherlock was doing, but was unsure if he wanted to know.

"I'm observing the effect of different acids on various body parts," Sherlock tells him, his eyes flicking lazily to the little dish beside them.

"Oh – right. Good."

John takes a small sip of his tea; his eyes fixed somewhere above Sherlock's left shoulder. The detective follows his gaze, wondering why. Avoiding eye contact was usually an indication of awkwardness between people, but this was not something Sherlock felt they had ever encountered.

"Everything alright?" Sherlock asks, already getting a hunch from John's expression, but deciding to follow social convention for once.

He regrets the ridiculous decision almost immediately. John's answer (while written all over his face) is voiced painstakingly slowly. The doctor considers the question for about a minute before deciding to divulge his problem. Sherlock wishes he'd just announced it to him straight off.

"Sarah's going abroad for a few years."

Excellent. He'd suspected some kind of extended leave on her part: John seemed upset, but not enough so for it to be a break up in the usual sense. She was going away; but presumably at this point they hoped to be able to negotiate some kind of long-distance relationship. Pointless. Jealousy always got in the way; that and not seeing your partner for months on end. He voiced some of this to his flatmate, who did not seem to find the notion comforting.

Sighing, Sherlock recognises a change in tactics was probably needed.

He watches John for a few more seconds. He was down, but not distraught, calmly sipping his tea, and seemingly lost in thought.

In two strides, Sherlock is standing in front of him, which at least manages to pry John's eyes from the opposite wall, at which he had been staring for the last five minutes. His eyes search Sherlock's face, slightly alarmed. He's probably standing a bit close, he realises, and shuffles back a bit.

A curiosity begins to gnaw at Sherlock's mind: he looks at John, looks away again, looks back. It's nothing indiscriminate, just a thirst for knowledge, a desire to know his flatmate's reaction, to see what he can deduce from it. Not unlike the fingernail experiment, or indeed any experiment he had ever done.

He hesitates for a second, something unusual for him, and he catalogues it for future reference. Then, his usual confidence returns, and he closes the gap between them, touching his lips to John's.

He surprises himself by how pleasant he finds the experience, and even though he knows lips to be a hundred times more sensitive than fingertips, it is surprisingly nice to feel John's lips brush against his own.

He catalogues several things. Firstly, John's lips are dry – but not unpleasantly so – from the cold weather, and chewing them occasionally when nervous. Secondly, he doesn't pull away as Sherlock half expected, suggesting the action not to be unacceptable to him. Thirdly, Sherlock is rarely at so close quarters with him: John smells of tea, faintly of disinfectant from the clinic, and the musty smell of clothes stored forgotten for long periods of time. It's nice.

Sherlock discovers that he's closed his eyes. He doesn't remember doing so, but has no inclination to open them, he is intrigued to find. Also, he notices that one of his hands has crawled, unbidden, onto his flatmate: sliding around the side of his neck slowly until his fingers curl around the back of it, and he can feel strands of hair tickling the tips. Furthermore, he observes that John's hand is, very tentatively, creeping up his arm towards his shoulder.

The kiss lasts maybe half a minute, until the pair stumble apart a little awkwardly, shooting glances at each other and smiling sheepishly.

Sherlock swallows, and looks at his flatmate.

"That was…interesting," he manages. He clears his throat, presses his lips together and inhales. "I suppose I was correct in assuming it to be a reasonable way to cheer people up."

John just shakes his head at him, chuckling a little, and returning to his cup of tea. His cheeks are tinged pink.

"Idiot," he says.

I was considering turning this into a series: kind of lots of different oneshots of 'Sherlock' characters kissing, similar to this one…if anyone thinks that is a good idea, then requests for pairings/situations would be very welcome. Just an idea. If no one's interested, I'll leave it like this.

Regardless of your view on the series idea, feedback of any kind is also very much appreciated.