An endurance competition requiring the participation of all residential occupants to determine how long a residence can be occupied without flushing the toilet.

In theory, the weight of defecation over time should eventually provide sufficient downwards pressure (gravity) to drive at least some effluent through the S or P-Trap at the base of the toilet, however in
practice the effluent often dries out leaving a crusty surface which eventually piles up over the bowel.

This competition is particularly difficult in circumstances where the water closet is located in a shared bathroom facility that is also used for showering, shaving and brushing one's teeth.

More commonly seen as a challenge of single males, this activity has specific adverse side effects should one of the male occupants get lucky and bring home female company for the night.
"...Hey guys - lets have a Mexican Shitoff. First to flush the toilet has to clean it..."
by Paul Claessen October 20, 2008
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When you're trying to take a dump at work, and someone is in the stall next to you trying to shit too. Neither of you wants to be the one to stank up the bathroom so you sit there squeezing your buttcheeks together.
Mary Sue and I were in a Mexican Shitoff in the bathroom.
by OhForF*cksSake March 27, 2015
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