Fully agree. If you get water too far into your bowels, then it will be there most of the day and you'll have accidents during a sessions. You want to evacuate the lower area but not touch the large intestines. I use an enema bag, but I don't kneel or bend over as this allows water to go into the intestines. I'll stand upright and give myself 2 to 3 enemas and then I'm good to go. This works fine for most strap-on play.

If you're going deep and/or fisting that's another story. The above works just as well but if they are pushing past inner sphincter, you want to make sure you're fully evacuated even with the contents of the large intestines. Then you don't want to eat for about 12 hours beforehand and you want to give yourself and deep enema. Then wait 1-2 hours before play so all the water has a chance to drain out.