Derived from the word "tattay" or balls or testicles. "Shaat" is slang for short circuit. Analogous to two balls being short circuited together like two wires. Used to define a situation when something goes terribly wrong with someone.
"Hey Max, the concerts tonight is in Hollywood right?"
"Yeah, but dude...I'm kinda not diggin' the scene tonight."
"Awww bro, don't be such a Shlaam man."