This is maddeningly slow, but wonderful in its own right, though Holmes will readily admit that it's difficult to experiment on someone's cock while that someone experiments with Holmes's. His thoughts are quite fragmented, torn between picturing Watson's every move and planning his own.

Incidentally, a moustache against his cock is a very unique feeling.

He takes Watson loosely in hand, running his thumb in firm strokes up and down the shaft; he busies his mouth at the head, teasing his tongue against it in every stroke and position he can think of. He isn't sure how long his patience will last, and he's poised to begin moving on Watson in earnest, but this state of exploratory limbo is rather delightful.