The shivering you get right before you unload a 10-pound dump into the toilet. This is followed by goosebumps, a flexed butthole, and a strange growling noise in your stomach telling you its time to unload.
Viktor: Dude, are you okay? You're shaking pretty badly.
Tim: Yeah, dude I'm fine I just got the shit shivers.
The shiver you get after dropping a deuce of substantial girth that tests the laws of physics. Like cold shiver but much more satisfying. In fact, very similar to a piss shiver, enjoyed after satisfying a tremendous need to drain your lizard.
Man, I hate dropping a deuce so enormous that it feels like giving birth & leads to rectal spasms. Hey, but at least I got to enjoy the inevitable shit shiver.