Honestly, I just give them a heads up about my pouch and try to explain it as effectively as I can. I do not like to hold back on my pooping to avoid causing more problems for myself. I let everything out when I need too.
Be who you are and say what you feel because those who mind don't matter and those who matter don't mind. Dr. Suess
Also too: you can always take your phone with you to the bathroom and play music so the people will not hear the farts coming out when its shitting time