I have quite a few different ways I would like to accomplish this.
1. Insert 1-2 bananas into my sub's rectum, then inserting a rolled-up feminine pad. Next, I would put a diaper on them, and then just wait until they messed in the diaper.
2. Give them the maximum safe dose of stool softener, then a few hours later give them the maximum safe dose of sennosides. A few hours after that, make them wear a diaper until they poop.
3. I'd give them a single dose of a stool softener, wait until they told me they needed to poop, and then I'd squirt half an ounce of glycerin inside of them, put them in a diaper and wait.
4. Get 3 dozen mini marshmallows and a cup of warm water. Make the sub get on their hands and knees, dip each marshmallow into the water before inserting it into the sub's anus. Once they are all in, put them in a diaper and wait.
5. Make them take a large dose of milk of magnesia. Once they felt like they were starting to need to poop, put them in a diaper.
6. I'd insert a long colon tube into their bowels, and insert a mixture of water and glycerin. Then I'd remove the tube and put them in a diaper.
If anyone has any other ideas, I'd be more than happy to hear them.
If you're interested in being on the receiving end of this play, either in person or online, feel free to message me.