When going to take a poop at work or in a public place, only to find that there is another person in the bathroom.
"Dude that was a quick deuce
"Well I was all ready to take a nice crap and this dude poopblocked me"
The one solid piece of poop that is stopping you from a diarrhea disaster.
Thank goodness that i had a poop block during that party or else things would have gotten ugly!
When you really have to go poop but your wife, your girlfriend or kids do not want you to go poop because it will stink the bathroom.
Husband: Hey are you done with that magazine I really need to go poop!
Wife: Don't go and poop in there!! I need to do my make up! Wait till I get done!
Husband: Do not be a poop block!!!!!!