The Doctor's mind, while thoroughly filled with Jack's pleasure, was also bubbling with a smug sort of self-satisfaction. He liked making the great Jack Harkness feel this way, especially coming after the pleasure he just gave him.

His mouth lowered again, and he traced his tongue along the base, swirling carefully up to the tip, then back down. He then took him into his mouth, copying the movements he'd felt Jack give him moments before.

I do pay attention.