Someone who pretends to be cool with you for at least two weeks, fucksyour sister, and nobody heres from them agin.
"Dude, he must be the sister fucker bandit, he was just hanging out with me last week and fucked my sister some time last week, I havent seen him since last week!"
A husband or boyfriend that has female best friend that he says "she is like a sister to me". When in reality, he is cheating and is actually fucking the female friend.