A nice way to say Slag, Slut, Whore ect....
It is called 'Pineapple brain' because they are very stupid (the fruit part of it) but they have 'Saucy' thoughts. Saucy being like 'Juicy'..... you get my drift?
Girl 1: OMG did you see Emma flirting with John today?!?!? She is gonna be shagging him next week!
Girl 2: I know, she is such a pineapple brain!