When my boyfriend and I have sex and I am on top, it sometimes gets rough. When this happens, the condom sometimes comes off.

Last night, 2 different ones came off. One was up inside of me and I had to fish it out. The other we noticed before it got pushed up in.

I am on birth control, but we still use condoms most of the time. Occasionally we do it without one, but not often because I am sort of paranoid about pregnancy.

Is there any way to prevent this from happening? We have tried several different condoms/brands. He is an average sized guy (5ish inches)