When I'm able to load my diapers (when I'm alone in the house or staying at a motel) here's what I typically do: I'm a morning pooper, so, I'll diaper up at night, drink lots of water, go to bed, and wet them all night. The next morning I wake up and they're warm, soaking wet, and wonderful. I'll wear them around a while, drink a big cup of coffee (which kind of acts like a laxative--I guess it's the caffeine), wet them some more, and when the time comes, I'll stand up and load them like a naughty toddler. I'm not into the "oops I had an accident" aspect of it, nope, I'm doing it intentionally because I'm naughty. I know better, I can make it to the toilet if I try, but I don't because I'm a naughty toddler. After doing it I then slowly sit down and enjoy the feeling of it mashing all over my bottom.
Then I'll sit in it for 3-4 hours, then go spread out a big towel on the bed and get myself off in them (I hump them and rub them against me, sometimes I'll stand up and sit back down to feel them squish around--it doesn't take long until I go off like a rocket). Then I clean up and "dry out" for several hours before getting diapered again. That's about the longest I can stay in them without getting a rash.
I know this because, in the past, I tried wearing them much longer. Once, when on the road, I wore my diapers for the three hour drive, arrived at the motel around supper time, and stayed in them during dinner. After dinner, while still in the same wet diapers, I went out around nine o'clock and walked all the way around the perimeter of the motel wearing nothing but diapers and plastic pants (that's another story!). I then got back to the room, pooped them, and went to bed that way.
And the next morning, boy, was I sorry. I had the worst diaper rash I've ever had. It took days to get over it. Now, I'll admit, for some people, the idea that you're a baby with diaper rash is kind of a turn on. When you have diaper rash and you're in dry diapers, the first time you let loose and wet them again, well, that feeling is something to experience. It's kind of a turn-on, but not very pleasant (especially after you get yourself off and you still have diaper rash). So I'm glad I've experienced this, it's a really "baby" kind of feeling, but not something I really want to do on a regular basis, if ever again.
But if I did that's how I'd do it. I guess different people's skin reacts differently, but for me, poopy diapers seem to cause diaper rash about four times faster than pee diapers do.