I sit in my poopy diaper all the time. I am bladder and bowel incontinent and when I poop, it always comes out in 2 or 3 waves. The waves are far enough apart that I don’t have any choice but to sit in my poop. After it happens so many times, you stop caring and just deal with the mess afterwards. I frequently poop in my sleep as well so I also frequently wake up in a poopy diaper.