This happens after you have been
constipated from a piece of stool that backs up your bowels, causing bad enough bloating that you end up getting severe intestinal pain, often
in the middle of the night.
When that piece finally gets passed, usually after several minutes of straining, groaning, and wincing, everything it was backing up immediately comes out as diarrhea, causing your ass to imitate
popping the cork on a bottle of champagne. Ironically, shaking your intestines, whether with your hands or making your legs shake up and down, can assist, in the same way you can shake up champagne to make the cork pop out.
Joe: Ugh, man I shouldn't have eaten that grilled five-cheese, wings, and beer at the pub this weekend. I woke up last night feeling like my gut had a knife in it. Took like twenty minutes
on the toilet before I finally ended up popping a cork.
Dave: You think that's bad? Last time I popped a cork, I'd had an
egg salad sandwich for lunch. I had to sit there with Egg farts the
whole time. I nearly puked.