In increments, Sherlock's attention begins to wander. His gaze turns, flicks here and there from the book in his hand to John and back again. There isn't much he misses, even amongst the subtlest of observable facts, and subtle John's relish of the proceedings is not.

Not exactly, anyway. Sherlock has already known him long enough to know that his genuine disapproval wouldn't manifest like this. These are token protestations, where protestations exist, and the rest...

Sherlock smiles to himself, because the rest is enjoyment. All evidence points to John rather liking this silliness, which is pleasing, and not merely because Sherlock does too. Not merely because they can share this.

The truth of the matter, the horrible truth, is that Sherlock is very much going to enjoy teasing more of this sort of behaviour out of the upright John Watson. Not because he wants to corrupt, or not exactly. He does want to help, though. He does want to see all of what John is capable of, so that he can accept all of it and carry on, as friends do. Or as friends should do, anyway; Sherlock sees it only rarely.

He means to be better. The best. He wants all of John's most honest moments for himself.

"Mm," he agrees. "And by the look of it we need the practice. No aim at all."