The penetrating partner then pumps away at the receiving partner's vagina or anus with his penis. It is up to the individual to discover what feels best to them. People may engage in anal intercourse, which has health risks, because the anus is full of nerve endings, making it very sensitive. They trust though that you will not harm them, so it is important this first time to be good otherwise you might not be given a second chance. Partners can be lying side-by-side, lying one on top of the other, or standing with one partner holding the other upside down.