To test my limits, on two occasions about a year ago and a month ago (just to make sure I wouldn't do it a third time) I used one quart of molasses (two jars) and one quart of milk, very slowly warmed on the stove to 100 degF. I used a double balloon nozzle and retained it for fifteen minutes.
It was not very hard to retain and the powerful cramps didn't start until about ten minutes into the retention. After the fifteen minutes of retention, when I was on the toilet half way through the expulsion, I started to feel a little light headed and nauseated. After I had expelled most of it, I had to lie down on the floor to relax. After about ten minutes lying down, I got back on the toilet for the final expulsion. It took another half hour before I felt like myself again.
I won't do that much of each ingredient again. It would be an excellent punishment.