when your external anal sphincter can no longer withstand the pressure exerted by the gravitational pull of your feces comming out of your bung hole, if this occurs other than over the toilet, you have now just began shitting your pants.
Holly shit, jenna must have been prarie dogging becasue she sure as hell stank like ass when she walked by, her momma's gonna be doing some laundry tonight!
When one's shit acts like a prarie dog, fanatically poking it's head in and out of it's home expressing it's urge to be freed from the confines of it's hole, but only when it is safe.
(See movie Rat Race)