Fuck bitches, get laid. This relates to girls who are sick of other girls drama and bullshit and simply wants to have sex, a similar outlook to that of a guy. A girl who says this is not necessarily a slut, she just knows what she wants and what is important in life. The girls who judge her are most likely prudes or celibates and are probably the ones referred to in the "fuck bitches" clause.
Cool girl: "All I want to do is FBGL."
Annoying girl: "You sound like a prostitute!"
Cool girl: "Sorry, I'm not sorry. I'm a chick with a dick."