Holmes ticks off the physical symptoms of arousal he is experiencing, an entire checklist full of them. And yet when it comes down to what he ought to do about it, he isn't sure what the outcome will be.

Nor is he sure how, exactly, to go about it. Not with Sherlock, who is far more difficult to predict or manipulate than he would have expected. He proceeds with care, lower and lower, until the palms of his hands can run over Sherlock's hips, to cup his ass, to massage the backs of his thighs. That was an area Sherlock had mentioned, he recalls, but he's sure Sherlock hadn't meant like this.