The insult used as a last resort if the other person has said something diabolical and so nasty that they shouldn't live in this world any more. It literately means a horrible, spiteful person and it used mostly in circumstances that can not be retained from.
1. Poo poo head (pronounced pooh-pooh-head) Is used when someone has done something extremely bad.
2. Can be used in a carefree way for children.
Mike: Haha, I heard that your hamster died of diabetes LOOOL
Luke: That is the worst thing you could ever say. You sir are a poo poo head!