Stare out the window

You take your seat as the bus starts to lurch forward, and you gaze off into the outside beyond the buses window. The sky is white with its blanket of clouds, and it looks cold, fitting for this December month. As you look on, you begin realizing how warm and comforting the constant stream of piss and poop coming out of your "soiled" pants feels. Though you would normally find it disgusting, the warm brown liquid tricking down the side of your legs gives you a sense of security and freedom you did not have before.

An idea pops into your head, and you tighten your stomach causing you to poop out harder. The feeling is incredibly pleasurable, so you continue doing it, grunting and sighing as you continue to forcibly gush out pee and poop onto the bus seat. As you get into it, you see others on the bus begin to do the same, likely inspired by your action. Soon, the entire bus is full of people in the midst of orgasmic defecation.