Co-Dumper

A person who is inside the stall next to yours trying to take a shit, where all you can identify them with is their shoes. After both you and your Co-Dumper are seated with asses exposed, both will attempt to stifle the sounds of bowel movement in order to avoid embarrassment. In extreme cases, silence may persist for quite some time until the pressure in the ass of either you or your Co-Dumper builds to extreme measures, and a loud disgusting gust of gas is released. With the silence broken, the other person now feels comfortable releasing their own gas which they have been painfully harboring. Usually at this stage, you and your Co-Dumper have built a bond, and will now shit in unison. The first to finish will quickly flush and wash their hands (or not), and purposely leave before the other person emerges from the stall in order to keep your identities a secret from one another. Later on, you may notice someone wearing the same shoes as your Co-Dumper, and an awkward moment arrives once again as the two of you pass by in silence with your heads down, hoping that the other didn't notice that you were their shit partner just moments earlier.

Derek: "Man, what took you so long in there? We've been waiting for 30 minutes!"

Alex: "Sorry, I had a Co-Dumper. It took a while for him to blow. I promise, I began excreting immediately after I heard his plops. Shit, don't look, I think that's him walking by right now."