The first time they kiss is at a crime scene. John is pleased and Sherlock is pleased that John is pleased, and he simply leans in for a kiss without thinking. It's tentative and fragile and when they part John's eyes are wide not because he's surprised, but because he isn't.

…it's at a crime scene and John's just said "Amazing," once again and it's the most brilliant thing that Sherlock's ever heard anyone say. He grabs John by the shoulders and kisses him hard. It's possessive and triumphant and says "He's mine and I'm his."

...it's at a crime scene and John kisses Sherlock because Anderson and Donovan have sniped at him again and only John can see how it bothers Sherlock, although he'd deny it. And suddenly, it's too much for people to think that Sherlock is sociopath and that John is his pet. So he reaches up to wrap his arms around Sherlock's neck and pulls him down into a powerful kiss to dispel those rumors once and for all.

…they're walking away from a crime scene, and Sherlock says, "I'd be lost without my blogger," and John knows it means I love you. So he takes Sherlock's hand and turns him so they face each other. "I'd have nothing to write about if I hadn't met you," he says and then runs the back of his finger along Sherlock's cheek. Sherlock looks surprised for once, and John takes advantage of it to close the distance and just brush his lips against Sherlock's.

…Sherlock's just been rescued by John from the assassin who cornered him in a narrow alley. 'It had only just been blocked by construction and that was the only reason that he'd been trapped,' he's muttering angrily. John yanks Sherlock's head down by his hair and kisses him bruisingly. He lets go and screams into Sherlock's face, "WHY MUST YOU ALWAYS BE SUCH AN ARROGANT IDIOT?"

…John's sitting with an orange blanket around his shoulders in the door of an ambulance. His black coat is ruined by the deep slash across his upper arm that's only just stopped bleeding. Sherlock shoves the medic out of the way and pushes into John's space so tightly that John has to lean back. He kisses John as if it's the last time he ever will instead of the first. "You don't do that for me, do you hear me," he says when at last they separate, "You don't do that ever again."

…it's at Angelo's and Angelo has brought over the candle. He says, "Oh, a one year anniversary. So special." They look at each other and realize that it is. Leaning in they kiss one another. It's a little clumsy and neither can believe that they've missed this vital piece of information for so long. Unnoticed by them, as the kiss deepens, Billy passes Angelo a ten pound note.

…it's in front of Mycroft. Mycroft has just asked Sherlock to join the shadow-shadow cabinet again and then asks John if Sherlock is hellish to live with. Again. John says, "No, not really," and starts to close the space between them. Sherlock grins and meets him mid way for a big smacking kiss. "I'll post the banns, then, shall I?" Mycroft asks drily.

…they're pressed together in a tight space listening for footsteps. The gun is drawn but the safety is still on. John can hear Sherlock's heart pounding, smell his aftershave, the wool of the coat, the slightly buttery smell of his skin. Sherlock looks down at him. That's all it takes. By the time they part, the suspect is long gone.

…they're walking across Hampstead Heath. Puzzle's solved. Lestrade's been called. The night is pleasant. Sherlock realizes abruptly that John has fallen behind. He waits. John looks up at him frustrated but grudgingly accepting. Sherlock says, "I'm sorry." He slides his hand through John's soft hair and pulls him close. John's mouth is slightly open and then so is Sherlock's.

…it's in the hallway of 221b after a zany adventure that saw Sherlock leaping from a moving cab and John leaping into another. They're flushed with adrenalin and euphoria. They're both giggling,, not laughing like grown-men, but giggling like naughty school children. "You do get me into such interesting scrapes, Mr. Holmes," John says when he catches his breath. He doesn't notice that Sherlock's stopped laughing until Sherlock's almost literally swept him off his feet in a disarray of arms and coat, as Sherlock kisses him so hard he's knocked into the wall and feels like he might be pushed through it. Not that he minds.

…it's on the couch of 221b. Telly is stupid and the people who want him to determine if their family heirloom is a forgery are stupid. Lestrade's stupid. London is stupid. In the middle of the sofa, Sherlock's sitting with his head thrown back, arms spread wide. "Oy, shove over," says John. "Booooorrrredd," Sherlock moans. There's a small pause while John considers something. Sherlock thinks it might have to do with selfish flatmates, but he's not sure. But then the couch dips slightly and there are soothing kisses in his hair, over his forehead, down his nose and finally pressed against his lips. And this could be interesting, very interesting indeed.

…John's in the consulting room of the surgery. A hunched old man hobbles in complaining of a pronounced pain in his chest. John turns to get a fresh pair of gloves and when he turns back Sherlock's standing there. It's been three years. John shudders, sits down and puts his head between his knees. He thinks he might be sick. Or he might cry. Or he might punch Sherlock in the jaw. Or all three. Sherlock sinks down next to the chair, "John," he says in his low, rich voice. John looks up and Sherlock's face is covered in tears. Sherlock's kissing tenderly. John's kissing angrily. He pulls away first, "You bastard," he whispers. He means it but they both know it doesn't matter.