John takes note of just how squirmy Sherlock is being, and assumes he's doing something right. Is now a good time to ask if Sherlock is really a virgin? John contemplates it, but doesn't say anything. Instead, he continues to nip and kiss the other's neck, while still pleasuring him.
The only thing John's not thinking about is how messy it might get when Sherlock is finished. But John picks up his pace none the less.