I make my own suppositories out of pure Glycerine soap. I put a block of Glycerine soap into my hand operated potato chipper so they come out as long slim chips (fries). As pure Glycerine soap bars are much softer than standard soap bars, they cut easily in the chipper. Even cutting the soap with a knife is easy, and it never crumbles, like ordinary soap bars do.
Just before insertion, I place them in warm water for a few seconds. This makes them very pliable and slippery, easy to insert into the rectum without any need for extra lubrication.
Being pure vegetable Glycerine soap, they are quite harmless, but once they have melted, they make you want to go for a 💩💩💩 pretty urgently 😉.
You can speed up the action by reinserting a finger or two, into the rectum, after about ten minutes, and stirring things up, round and round, inside 😆. By that time, the suppositories should have almost fully melted, and it should be quite sloppy & soapy up there 🥰.
Of course, if they are punishment suppositories, now would be the time to fit the inflatable butt plug. Thus making the person retain the punishment melted suppositories, with all the cramping and urge to go 💩😈.