When a person has really bad diahrea where in they don't make it to the toilet fast enough.
Usually caused when a person who has gastrointestinitus has had to much to drink and eaten food stocks known for making green poop and/or large amounts of intestinal gas.
"Man, excuse meI gotta go!"
"What? You sick?"
(*running and groaning*)
(returns 30 minutes later.)
"Hey I got to leave."
"What? why?"
"I didn't make it onto the toilet in time and I sprayed butt soup all over the seat and the back of my pants.)