How can we make better when the guy bottoms out?

I'm a pretty petite girl & my boyfriend is really um gifted down there lol so whenever we have he bottoms out & hits the back wall of me or whatever that would be called. It hurts pretty bad whenever he tries to go all the way in because he can't because he's too big! How can we make it more pleasurable for me? He tries not to go in too deep but he still goes too deep sometimes & it hurts lol..