You don't want to be her friend, if you do, you are probably a slut too. If she's your best friend you are probably a bigger slut than she is.
She's like a fungus or HIV, when she has a hold on you then she is almost impossible to get rid of, she will also change everyone in to a slut by just being friends with them. Typical bad influence.
If however you were once considered a friend and are now either an acquaintance or an enemy then I salute you, you escaped the 2nd worst person alive. You are probably a strong gifted person that can see through her and chose not to get involved.