@trw428
You wrote "a little testy". Of course. That's exactly the point. In the solution, I've read the soap is included to bring the bisacodyl into better contact with your bowel wall, but the full effect takes a while to build. Bisacodyl, given rectally, doesn't really start to work for about 20 minutes. Consider, a Fleet Bisacodyl enema takes 15 or 20 minutes to act. Oh, you may well feel a burning sensation sooner, but it takes a while to really get the cramping going. And, that's what you really want... strong muscle cramps throughout your bowel.
You can get an idea of the cramping to be expected when this enema really gets going from the original patent, which includes a nozzle with inflatable retention balloon, but also a special harness designed to hold the recipient's butt cheeks together and prevent nozzle expulsion during retention. This implies that the urge may be strong enough to expel a balloon retention nozzle.
https://img.techpowerup.org/200529/clayton-harness.jpg
The recipient has the nozzle inserted and the retention harness applied and strapped tightly, compressing the butt cheeks, then the balloon is inflated to seal and the enema started. The recipient is moved through several positions while being filled to ensure the solution reaches all areas of the colon. Note that while there are many straps behind, there is but one in front, allowing very quick release at poo time.