You need to get together with her and the "friend" (with friends like that who need enemies - lol) and have him explain exactly why he started that rumor (he'll probably say to make you look good). This is a common occurrence. I remember a classmate freshman year of college that I took into my room (my roommate and another guy kept pestering me for a full "after action de-brief"). Unfortunately, I "broke" and told them how far I got (not all the way). They at least had the decency to not start a rumor about it, but my roommate referred to a "blow job" as "At least you let her do the dirty work" which seemed kind of disgusting to me at the time. I just chocked it up to his inexperience or lack of success with women. I don't talk about women like that and I sure don't pester friends to find out how far they got with a woman.