Can someone explain what sexual restrictions there are in Christian Catholicism? A divorced female friend of mine was dating a Catholic guy who was okay with having oral sex with her (giving and receiving), because they were not married, but not vaginal penetration. He talked about vaginal penetration being a connection of the souls but not oral sex. (He was okay with anal as well, but that was not her thing.) Is this covered in a rule book somewhere? I know that a lot of married people (celebrities and others) don't think of oral sex as "real" sex (and so will do it extra-maritally) and not consider it adultery. Can someone please explain this distinction? I've heard of this in other religions, but mostly in Catholicism.