I don't have that problem, because while as I write I'm distracted with all of the problems of writing, e.g. "is that the best word to use here", "should I use a period or a semi-colon?", "f***, I left out a detail I wanted to put in here", "I'm writing crap, but I need to keep going; it's easier to rewrite than to write out a scene for the first time."

Not to say I don't get distracted by arousal. But that happens during research, and when I'm thinking about what I'm going to write. Just not while I have pen in hand, or fingers on keyboard.