Chool it

Chool it is a portmanteau of "chill out" and "cool it". Used when someone is either getting angry at nothing or being a fuckwad. "Chool out" is an alternative form of the phrase.

Guy 1: I'M SO ANGRY RIGHT NOW!
Guy 2: Dude, just chool it!

or

Guy 1: Wow, John is such a fuckwad.
Guy 2: I know, he needs to chool it.