A euphemistic version of the Vulgar Slang, shit. Also the past tense for the Vulgar Slang.
Monster: Hey how u doin bro
Human: I shat my pants TM! Making the best games! (Interchangable for euphemistic version and past tense)
To mess up. To embarrass yourself.
I wanted to join my local football team but I was afraid I would shat it.