When you push and push to get the first part of a poop out, and then the rest comes rushing out behind once the hard part passes. Quite similar to the hardened piece of cheese in the tip of a cheese whiz can that hasn't been used in a a while, and takes a few seconds to pass, then the liquid cheese comes rushing out behind.
"I was pushing so hard to get the first part of my cheese whiz poop out of my body, that when the plug popped I thought my intestines were leaving my body"
by Honey Blumpkins January 21, 2017