I never sent a dickpic in my whole life to impress a woman.
I mean, I sent many dickpics when asked for (and yes, there are girls that ask for pics in certain particular places) and received nudes, but I would never use a dickpic as a way to impress a girl immediately. I would feel odd to take out my instrument and take a picture randomly.
I would almost never deny a dickpic if asked, I would never send a dickpic if not asked for.
Simply as that.