pissed shitless
adj. used as an expression "pissed shitless," referring to being so angry as to cause the spasming of one's sphincter muscles, causing the bowels to release and resulting in the defecation of one's pants.
Guy 1: Remember when that waiter got your order wrong and you yelled at him?
Guy 2: Yeah, I was pissed shitless.
Guy 2: Yeah, I was pissed shitless.