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A dam inserted into one's large intestine, or colon, to prevent the sudden blast of diarrhea. The damn is attached to a metal chain for easy access to pull out when you are ready to empty your build-up.

The diarreahphragm is inserted by a large metal pole.

The diarrheaphragm can lead to a common and severe disease called diarrheabedis. This is because of the massive build-up of diarrhea, and secretes "pup" through various exits of the body. "Diarrhea simply has nowhere else to go."
Good thing I have my diarrheaphragm, otherwise my wedding would have been ruined if I accidentally diarrheaed.
by David Lieber Mintz January 09, 2011