A fart accompanied by a loose, muddy shit that *almost* makes you shit your pants, but instead splashes against the inside of your colon. Sometimes accompanied by the dreaded burning sensation which indicates major ring sting and diarrhea in the near future. You ate something really dangerous.
Imagine a wet fart which never leaves your ass. Colon Splash! You got lucky my friend, but find the nearest bowl or bucket.
I just had a major colon splash!