John wishes he could pinpoint the exact moment he stopped correcting people who assumed they were a couple. It was a difficult kind of thing to put a finger on. He would have liked to question and analyze it and worry it like a loose tooth, that one particular moment, but he can't and it's very irksome.
Of the two of them, you would think the one with the greater tendency toward obsessive self-analysis would be Sherlock, but it isn't. Sherlock has always gotten along very well with his own mind (his very first flatmate, in a way) and he's never surprised by what it ends up doing even if he doesn't always pay attention to why. It tends to warn him before it does anything truly alarming, anyway. That is precisely why the human nature of other people is so fascinating and confounding—because he's so used to his own brain and everyone else's is so different.
He rather wishes John wasn't so concerned with remembering the last moment of "no, we're not a couple." John hasn't said anything, but Sherlock saw the question form behind his eyes—or more specifically, the little crease between his eyes—once at Angelo's. The site of their first not-a-date, which was probably what made him think of it. Sherlock, of course, knows the moment John is searching for. It was about a month ago in lack-of-response to Sally calling John his boyfriend. It was a rote jeer, off the cuff, just because "sidekick" and "lap dog" hadn't fit her mood that day. And John was going to say something to her, was just about to, once he finished this thought to Lestrade, and then he didn't, because there was a dead body and the grown-ups were talking and there was just no time for Sargeant Donovan. Sherlock saw it happening in John's face, and he remembers it because he was proud of John for, once, not being dull.
Sherlock knows the moment John's looking for, but he doesn't say because he also sees in the wrinkle of John's ophryon the intent to analyze it, and that would be almost as dull as rising to Donovan's bait for the dozenth time.
He is not worried about extremely straight John analyzing himself into a right panic and rushing off to marry some nice straight woman and have nice, straight babies. He is not worried about this because of the two of them, John not the one that usually goes rushing off into things but also because (in a train of thought suspiciously like how he relates to his own mind) he feels sure that if John were ever to lose the plot completely and do something alarming, he would warn Sherlock first. Perhaps in a text, or a note on the refrigerator. Have invented imaginary sexuality crisis for myself. Likely to propose marriage to first female person I meet. Please intervene accordingly.
But there is no such note, so Sherlock does not worry. He watches from the corner of his eye as John pauses in making the tea to search for the moment again, and Sherlock says nothing.---
Sherlock is surprised that he can't pinpoint the exact moment his personal bubble broke down.
He isn't sure why most people assume he's not a physical person. Human relations wise. What some people call "touchy feely." Awful phrase. "Physically affectionate" doesn't really work either, since it doesn't always hinge on affection. "Physically demonstrative" is closer, since there are lots of things one can demonstrate.
Anyway, he is a physical person. He thinks it should be obvious. Everyone calls it "no sense of boundaries" and "disregard for personal space" and shudders at how he has to see touch smell taste at every crime scene… and yet everyone also assumes he would be averse to physical contact. Really, just when he thinks he's figured out how other peoples' minds work, they find an even stupider way to go about things. The only reason he keeps his distance from people and not from corpses is that the living have a tendency to take issue, and he wouldn't normally care but they do go on about it, and it tends to distract from whatever he needs them for. He noticed this many years ago, and so he set a rule against it for his hands, instituted a shell of space between his body and others', like everyone else had. Touching is a bit like crying, now; he'll do it to shock, to manipulate, but never involuntarily, never just because he felt like doing it.
He doesn't even remember the first time he touched John casually, involuntarily, just because he felt like doing it—a hand on the arm, shoulder butted against shoulder, long fingers picking something from John's clothes or hair. It is remarkable that he does not remember, that he broke the years-old shell in a nothing moment without even noticing.
By the time he finally caught himself, Sherlock had moved on from plucking John's sleeve to get his attention to grabbing John's hand to drag him down an alley on a chase, to just leaning on him: elbow propped on John's shoulder as he watches John text, sitting back against John's shin as John watches telly and Sherlock researches on his laptop, slouching against John standing as one might against a door jamb when things are being dull.
Anderson witnesses one of these latter moments while they're being debriefed by Lestrade and sneers predictably. "Congratulations, you've made furniture," he says to John. "If you're actually aspiring to be his doormat, though, you might have to lie down first."
"I'm just not confident enough to attempt doormat yet," says John smoothly. "I feel like I need a transition object. A mop, maybe. Perhaps you could demonstrate by standing in the cupboard over there, closing the door, and being quiet until someone fetches you."
Sherlock tries not to look at Anderson or grin. In the former he succeeds; in the latter he fails miserably. He leans on John a little more showily. Lestrade rolls his eyes. John only stands up straighter.