Actually I was given one once when I was 8. because we were meeting my grandparents for lunch on a Saturday and there was no time for an enema. Dad said "It might solve the problem, but it will at least stall things for a few days til we ca.n do an enema."
He actually explained to me how to self-administer in the Simms position and gave me an adult glycerin suppository on a clean washcloth.
I took off my jeans and panties and took it on my bed. After 5 minutes Dad knocked on the door. I pulled the covers above my waist and told him to come in. He said, "Actually, it's NOT like an enema, get dressed and be up walking around It actually works better that way," I did that, and when I got out of the bedroom he told me, "It will take about 15 minutes to fully melt and that's when you should start feeling it.
After about 35 minutes I got what looked like a normal large bowel movement, but was more uncomfortable than a normal movement.
We both thought that was about it, and started getting ready to go out for lunch.
A couple of hours later we were at lunch in a nice place.
About halfway through lunch I just had to excuse myself to go to the girls room I talked Grandma out of going with me, and it's a good thing two, because what came out was essentially brown liquid liquid, I put myself back together and finished lunch. Then when we were shopping I had to go again. After that it wasn't much different from having taken Milk Of Magnesia.