So my boyfriend and I have a very active sex life, and we are always ready for round 2..3..4 but SOMETIMES after the first round (mostly after the second round) I will get super sore at the bottom  of the opening of my vagina. It won't hurt when we do other things as long as he isn't pressing against the bottom of the opening, wth is this? Should we just stop having as much sex.. Cause I'd rather not. Hahaa or is it something I could prevent ???