If I were you, I would discuss it very openly and honestly with him but approach it very positively, (so he won't feel you are complaining about him *not* doing it,) Make it sound exciting! Like start out...I've been having this fantasy that I really would like to try...let me tell you about it. And when you describe it to him, be sure and include how you think it would make you feel. (sexy, moaning with pleasure, naughty, etc.--like pitching an idea!)
You have got good answers.. close the question..
Get rough with him, that signals to him that it's okay to be rough and he will typically be a little more rough from then on. Also, things like this should be discussed...
Ask him to naked wrestle with you, broke the ice for me.