I would say don't think about clit as much in this. You should both excercise your P.C. muscles and then flex at the same time and it should be amazing for both of you.
If you masturbate (especially if you do it often, or even used to) it might be because you're used to doing your own thing, doing what you're used to, because you know it works. If he feels bad about it, first I'd explain that to him so he doesn't think it's his fault. And then? Climb on top and do whatever it takes. Guys NEVER mind when a girl does that.
