It goes on forever; their first kiss. Is it still their first kiss? Sherlock’s lost track of time but he’s still got a good bead on space, and he’s absolutely certain that their lips haven’t yet broken contact. Then again, John isn’t just holding their faces together, motionlessly. Thin lips, slightly chapped, purse and stiffen against his, then soften and open and huff a little breath against his skin before closing again in a little nip. And he’ll sometimes tip his head one way or another, smearing the kiss messily as he maneuvers around their noses, and then settling back with a contented hum. These seem like separate kisses. How is Sherlock supposed to keep track of how many kisses they’ve shared if he can’t even figure out how to define their boundaries?
He gives up on cataloguing anything except for the points of contact between them, ignoring everything that isn’t John, and John holding him, and John kissing him. John mashing their lips together and then pulling ever so slightly back so that he can murmur nonsense - gorgeous, amazing, God you’re just so, oh, beautiful - into Sherlock’s mouth. John slowly scratching his way up Sherlock’s sleeves and raking blunt nails down Sherlock’s back, making him arch and shiver and squirm. John shuffling a little closer between Sherlock’s knees and making him gasp and whimper by combing his fingers through dark curls and then making a fist.
Consciously blocking out the night sounds of London and then letting little things like the passage of time slip away leads to more and more connections to reality coming unraveled, one by one. Sherlock forgets to breath until he’s forced to gasp in air, forgets his own name because he’s so focused on John’s, forgets to feel awkward about not knowing what to do with his hands because he’s lost track of them entirely. He’s unmoored, adrift and content to be so until John pulls back, breaks the kiss, - first? hundredth? - and murmurs,
Sherlock hears it but he’s still too dazed to consciously react, blindly seeking the return of John’s lips with all the unabashed desperation of a newborn at the teat. John chuckles, soothes and stops him with a soft nuzzle.
“Sherlock,” John murmurs, trying again to get his attention. A warm hand cups his cheek, and there’s a thumb stroking the other side, straying now and again to drag across Sherlock’s lips. It’s near enough to a kiss to satisfy primal need, for now at least, and Sherlock’s lids flutter open.
“There you are,” John says, smiling warmer than his hands, the fire in the grate, the sun on the other side of the world. “All right? You’re shaking.”
Oh. Sherlock is surprised to find that he is.
“Adrenaline,” he mumbles, still a little woozy. “Hypothalamic signals sent via the autonomic nervous system to the adrenal medulla resulting in adrenaline being released. Binds to alpha and beta receptors, and…and regulates visceral…um.”
John is chuckling, and Sherlock feels his cheeks flush at the sound.
“That explains the dyspnea and tachycardia,” Doctor Watson replies, playfully solemn as he slips two fingers down to take Sherlock’s pulse. “Just needed to make sure it was a good adrenaline rush, and not fight or flight.”
Sherlock shakes his head, feeling a bit more present in the conversation now.
“Nor freeze,” he adds a little breathily, “though I could make an argument for fawn.” He wants to fall to the floor before this man and worship him, and even more than that he wishes desperately that he knew how.
John’s eyebrows quirk up and he hums, but doesn’t abandon his main pursuit of looking over his partner and patient fondly. He stops pretending to check Sherlock’s pulse and instead holds the man gently by the shoulders.
“What do you want now?” John queries, calm and quiet, and it sends a thrill of possibility through Sherlock’s frame, top to toes. John seems to feel it, because his hands tighten reassuringly along Sherlock’s upper arms as he adds seriously, “Whatever you want is fine, Sherlock. We can stop and talk about it, or move to the couch for a bit of telly and a cuddle, or if you need a break you can go…dunno, sweep your Mind Palace or do something with those mice in the fridge. There’s no wrong answer.”
It speaks to how far off its usual foundations John has rocked Sherlock’s state of mind, that the detective doesn’t immediately begin formulating an answer designed to test that statement. Sherlock tries to think clearly, gives it up as a bad job after a moment, and then tries to pin down what he wants most just now.
“The couch option sounded good,” he says hopefully, with a tiny bit of embarrassment mixed in. “Could we, um…also continue what we were doing?”
“Of course.” John grins, bright and happy, and he gives Sherlock a kiss right away as if to prove it.