The journey to find a place to poo, eternally extensive at the worst times. Will often entail speed-walking (or running if it’s bad, or hobbling if it’s painfully bad), furtively entering
restaurants, grocery stores, etc. (and when
caught in the act, lying that you did indeed buy something from that establishment), and at least one question to a concerned passerby regarding the location of the nearest bathroom.
Portmanteau of shit and excursion.