@service1010 Empty bowels, including gas. Mostly,I was instructed to have a good BM the morning of the simulation (which was in late morning). That is my usual MO, so I required no extra stimulants.

Looking back, and knowing what I know now, I would have also laid off eating beans, legumes and cruciferous vegetables a few days before to minimize any gas. Fortunately, that wasn’t a problem for the sim.