Almost obscene really isn't the phasing for it. John can't help but open his mouth half way, as if furthering that train of thought. He wipes his thumb almost clumsily against Q's bottom lip even as he hisses out a little moan.
"Christ," he says, and isn't sure if he said that yet or not. Not that it really matters. With his other hand, he adjusts his stroke, shorter but faster until he stops completely in order to brush the pad of his thumb over the tip of Q's cock.