This is not advice that has much effect on pleasure during sex but it can make a big difference afterward and for the next time around. The basics of good sexual health are something most people understand: use protection and get tested. But there are a couple more tips that men should keep in mind for their female partners. For people having anal sex, never switch from the anus back the vagina because that can introduce E. coli bacteria into the vagina, causing infection. It's also a general rule that women need to pee post-sex to avoid urinary tract infections. This information may seem sterile but knowing it is very sexy.