Many years ago, I did some experiments. First, to be sure I'd come to no harm, I did them with an inverted jam jar in the sink. The technique is to mix powdered laxative fizz with glycerin. Here I can buy it as Eno's Fruit Salt - but it's the same stuff as Alka-Seltzer. There is no reaction as pure glycerin has no water content. I took a teaspoon of this, thrust it into a jam jar full of water, and then quickly inverted the jar in a sink full of water. As the water began to dissolve the outer edges of the glycerin, the laxative started fizzing a little, then faster and faster and in about three seconds, the jam jar was full of CO2. I wanted to find out how much gas I got from how much powder before I tried it up my bum!
Well, finally I worked out that about a dessert spoonful of powder in glycerin produced a litre or so of gas. The problem was to get the glycerin/powder mixture up my bum and then add water. I solved it by mixing the powder and glycerin in a party balloon. I didn't tie the neck, but just twisted it well, and then shoved it by hand up a well-loosened anus, pushing it well beyond the inner sphincter. Then I used a Higginson syringe to squirt just two bulbs full of water up me. I was hoping that the water would give enough space for the balloon to untwist its neck, so that the water could get in and start the fizz. In suspense, I waited. For a while, nothing happened; but eventually the water found its way into the balloon. I felt a mighty rush, and was almost instantly full of gas and glycerin. The CO2 seemed to make the glycerin even more irritating than it is by itself; I hardly had time to get to the toilet before I was unable to hold back, and with a mighty trumpet blast, everything came out like a JATO rocket.
After the initial rush, the powerful urge to expel what was no longer inside me continued for quite a while. I never repeated this though the
effects were spectacular, as the hassle factor was too high!
Johnny