Refers to a state of gastrointestinal distress usually resulting in premature defecation; unwittingly shitting on the toilet, not in it.
While donuts make me go nuts, Timbits give me rim shits.
The rim of shit around the water’s edge on an uncleaned toilet.
Ray: Damn dude, I had to drop a massive ass blast in the bathroom but there was a shit rim so I just did it outside
John: Bruh it’s just a shit rim not like ur gonna die