Do not assume you both want the same degree of intimacy. Protect yourself from a charge of rape because you didn't ask. Being drunk or stoned is no excuse. Having sex with someone who is, is rape. It's a Crime.
Men can be victims of rape and have the same rights to counseling and legal action as women do.
The single most important thing a rape victim can do is tell someone - the police, a friend, the rape crisis center, a counselor. Don't isolate yourself, don't feel guilty, and don't just try to ignore it. Rape whether by a stranger or someone you know is a violation of your body and your trust. Don't shower, wash, douche, or change your clothes, even though that's your immediate reaction. Seek medical attention.