It is similar to being cock blocked, but instead of getting blocked (or prevented) from scoring a potential hookup, you are being blocked (or prevented) from letting your poop out.
Getting "poop blocked" tends to happen in a work environment where another party comes into the bathroom and occupies the stall next to you while you are trying to poop. You experience an awkward silence, making it too embarrassing to push your poop out since there would be a loud splash sound going "plop, plop, plop" into the toilet. Additionally, the person in the next stall now knows what your shoes looks like, which can be dangerous as he/she can now identify you around the office.
Abbreviation: PB'ed
Brenda: Damn it!! I got poop blocked for the 2nd time today!
Erica: So you were prairie doggin' it the whole time...
Brenda: I had to retract so I can go back later to continue my extraction.
Erica: I gotta go now... Hopefully I dont get PB'ed!
You've been stuck somewhere, usually a meeting involving your boss and you have to take a poop real bad. You somehow endure the pain of going through the entire period of the meeting to the finish and then you run to the bathroom. Just as your about to enter the only stall someone jumps in and occupies the toilet.
That person who brazenly cuts in front of you in line for the bathroom, fully aware of your urgent intestinal plight. It's as if they take pleasure in your discomfort, making their act all the more infuriating.
"Honey, please donβt be a poop blocker when we get home. Iβm crowning and it won't wait."