I get the nervous shits before a workout. Kindof like a pre-war strategy so to speak, that my body uses to best ready itself and get rid of any extra bulk. Some people puke, i shit(happened alot during my wresling tournaments when i was younger). Definitely pre workout, otherwise some very unpleasant things can happen at peak contraction or tension. Here are some funny stories about shitting that aren’t necessarily training related.
On another note, i carry a plastic bottle all the time for refilling with water. Well one time after a workout, i went to a movie. About 30 or so minutes into the movie, i realized i had to piss really bad. I didn’t want to miss any of the movie, luckily for me the theatre was mostly empty. I used the empty water bottle and filled it all the way up, i almost overflowed it(thankfully i was wearing mesh shorts and it was relatively easy). From then on, i made sure that i either just took a few minutes to go to the restroom during the movie or just go before the movie. I was kindof dissapointed though that i had to throw that water bottle away, it was my favorite one at the time.