Just thought of a couple more...
Space invader: this is the guy that comes into the bathroom while you're in a stall, and picks the stall directly next to yours to do his business. A one-staff buffer should be maintained at all times, unless of course, it's a two stall facility. If this is the case, a fly-by should be executed.
Down periscope: this is the act of lowering ones head below the level of the stall wall to identify the shoes (and possibly pants) of another pooper, especially if that person is a space invader. A subclassification of the down periscope is the Full Disclosure, which is the rare and horrifyingly embarassing instance when both poopers down periscope at the same time and meet eyes.