How do you make a reusable SHP in a diaper?

I have seen a few pics of where a person has a stuffed animal with a SPH that wears a diaper with one too and i'm wondering how the diaper SPH is done where the hole is clean and The stuff doesn't come out making it useless since i'm very intrigued and want to try it now.

Sorry, I'm missing what you are actually asking about? I think you want to know how to cut a hole in a disposable diaper, but not have the continence come out? Or, is it the stuffed animal you are asking about? Or is it both? If just the diaper, I would suggest putting thick sticky tape over the cut hole on both the inside and outside of the diaper, then cut a smaller hole through the tape. You could also look this up on Google, if its the stuffed animal you are asking about.

This is not my area of expertise.

If you want to make a disposable diaper with a hole . Get extra thick tape approx. 2 inches wide (like duck tape) it comes in clear for fixing glass houses. Apply to outside of diaper first then slowly make circles on inside of diaper pushing padding away from the outside tape area. When done you should be able to cut through without spilling filling. You may need a fabric tape to bond with inside and tape outside to give a sealed diaper just don't expect it to hold much liquid. lol. I hope this is what you were after.