After making the promise, he worries now that he won't be able to follow through on it, even though he doesn't think that too likely. The dominant positioning is doing its job to make Holmes feel more in control, even as Watson clings to him. Besides, taking Watson's cock in hand will complete the quest to reacquaint himself with Watson's body.

"Traumatizing?" he asks, not as amused at Watson's words as he ought to be, as he's too busy feeling aroused. He brushes his lips teasingly over Watson's, giving him the hint of a kiss. "What did you think of?" This question is serious, and he draws back enough to let Watson know that.