Ok. I'm clearly not a lesbian but I think I know whats going on here. It sounds like your friend is appealing because she is unattainable. It is a common attraction for people of both genders and all sexualites. Your friend is innocent and "untouched" and therefore the thought of "corrupting" her is exciting for anyone. It is not that she is necessarily cuter than you at all. I am sure that your lesbian friends were just kidding around. It is always fun to talk about someone that you can't have. Don't take it personally.