When I was in my senior year of high school I stayed the night at a friends place and we got high before school the next day.
I don't know why (i was unaccustomed to smoking tobacco with weed at this point, may be related) but it hit me in a really bad way when we were waiting for the bus outside his house.
I went from fine to needing to stuff pretty bad by the time the bus got there, and after about 5 minutes on the bus I was in panic mode.
I spent about half an hour holding myself against the glass at the back of the bus panting and draining every last drip of energy I had just in an effort to not stuff myself.
After a while I was certain that there was no way I was ever leaving this bus without a brutal eruption of the bowels and decided to just accept that, get off the bus and walk home with stuff smeared down my pant legs, my friend convinced me to just hold it until we got to the train station.
Through what has got to be the most intense period of concentration I have ever been through I made it to the train station unspoiled. However right as we arrived my need to stuff disappeared and I didn't bother going to the bathroom, a foolish mistake.
By the time I was on the train I was fast approaching the demise of my trousers, sweating heavily I clenched my starfish for all I'm worth until the train arrived and I was quickly ushered on to the last bus to my school, for a further 20 minutes or so.
By the time I got to school I was beyond distraught, physically and emotionally drained by the weight swishing about in my intestines, I don't even remember seeing my friend as I dashed for the closest toilet and finally relaxed and let approx ~2 kilos of potential spillage slide out of me before I got myself to the infirmary and passed the forget out for a couple hours.
Never in my life have I been so close to busting my breeches and in such a bad setting.
I thank my back door every day that I survived that morning.