A really horrible experience that is by no means good in any way shape or form.
May also be referred to in a sexual manner when someone engages in anal sex and shit literally ends up coming out unexpectedly either on the penis, toy etc...
Person 1: I just lost my job dude.
Person 2: Ouch, I'm sorry. I've never had that kind of shitsperience.
Sally: I let my boyfriend do it in my ass last night, and oh my god... it was a total shitsperience. There was shit all over his dick.