If you or your partner are a bit turned off or squeamish about real poo, but want to experience the feeling of a fully-loaded diaper, try making a large batch of homemade Play Doh. There are several recipes on the web. I recommend the ones that purport to be the same as the real Play Doh product. I call my custom brown colored Play Doh, “Squeeze Poo” because you can squeeze it by hand it into realistic shapes before dropping it into place.
If you want to have the experience of being a naughty little toddler, put a small turd of Squeeze Poo in your training pants before going out. Since it doesn’t smell strong, no one else will know about your little accident.
For coloring I used about ½ to 1 cup of espresso coffee in a batch of 2 to 3 quarts of the dough. The espresso gives it a pleasant smell as well, but it may cause some staining on fabric or plastic.
The amount of liquid is a key thing to consider. If it is too soft it has more of a tendency to stick to fabric (and your skin). Also this must be stored in an airtight container so it will not dry out. I like to make it about the same consistency as the real Play Doh product.
Remember, this is not for anal insertion. You simply drop the Squeeze Poo into a diaper, training pants, or into underwear for a simulated accident. You may or may not want this against your skin for long periods like overnight, but the recipes I saw were all pretty innocuous stuff (YMMV). Try warming it up, or even cooling it off beforehand for different sensory effects.
Of course if you reuse this stuff you may want to wash your hands after handling it, it’s been next to your butt after all.
(I would have posted a link to a recipe, but I am unsure of the rules here regarding the posting of links.)