A slutty girl who is shared by brothers in off an on hook ups, or bounces back and forth from one to the other, making the brothers hate each other.
Guy 1: didn't she just date your brother?
Guy 2: Yeah, but we've been making out
Guy 1: Dude, get rid of her, shes like your family slut.
Later that day, guy 2 gets his ass kicked by his older brother