Let's suppose your roommate's name is Mike. How about this: Every time they start picking on you, look at your roommate and ask something like "Hey Mike, does she still do that thing with her tongue in your ear while she strokes you? I loved that move!" That will stop the teasing!
Basically, your roommate broke the "man" code, section 27 paragraph 4: "A friend CAN NOT date anyone you kissed. Anyone you kissed carries the hands-off equivalency of "sister" status. If a friend wants to date someone you kissed, they MUST ask you for permission prior to engaging in any form of sexual contact. If your friend upholds these rules and asks permission then you are required (man code section 27, paragraph 2) to give him approval."
Your roommate's membership card has been revoked. Please confiscate it and cut it into little pieces.