So this morning my boyfriend and I had sex, and when he started “hitting it from behind”, I almost wanted to cum but then I felt my anus throbbing. It didn’t hurt, but it was throbbing so much i lost my focus in sex and didn’t cum. I thought maybe it was because my boyfriend was beating my pussy so hard that I felt the throbbing all the way to my anus. Idk. Has this ever happened to anyone? If so, what is it called and why does it happen?