I have no idea. I usually try to stay from those girls. Especially if I am interested in the girl, I don't want that brought up. Bisexuality is fine and all, but I just don't want the competition. Talking about sex is fine only if has to with me. =P That is incredibly awkward when women talk about sex with other guys. Not to mention that it's completely vulgar. Women should talk to their girl friends about this, not guys. I think it means that they are a tease and I would stay away.
I will do my best to reply with an educated, humble and honest answer. Ultimately, it is up to you whether you want to listen to my advice or ignore it completely. Sometimes, my advice may be wrong; occasionally, it will be right. Regardless, I want to do my best to give people answers they are seeking.