Honey, anyone who makes sexual advances without your giving permission (i.e. while you're asleep) is molesting you. No doubt about it. It's happened to me, too, and it took me a long time to come to grips with it. As a former sex ed teacher I can tell you there's virtually no chance of your being pregnant...but you should definitely get tested for STD's & HIV (test ofr HIV after 6 months, they can't always detect it before then.) Anal sex carries the highest risk of all sexual activities in terms of disease transmission due to tearing and the nature of the lower intestine. Buy some condoms, and keep them nearby. Have all the fun you want, just make sure you stay safe. You could regret it for the rest of your life if you don't.