C
it sounds like you're jealous! I wouldn't say this girl is a slut, I would say she's obviously making the most of her freedom. Sometimes a girl needs to feel wanted. Although there must be something wrong if she needs three blokes, it shows that they are all lousy and cannot fully satisfy her animal instinct.
But if she is still doing this in a couple of months time and everyone you know has had a go then she's a slut.
You should be friends with someone even if they have a better sex life than you. Who knows, you may actually get to be the only one that can please her.
