I've never experienced either diapers or frequent bed waiting. I do have a memory about age 7 at home in bed and wetting myself once or twice, but somehow mom and I got it under control. Never wet again. I recall it being an interesting warm feeling, but I wasn't enthused about sleeping in a wet, eventually cold bed.
However, I do enjoy two other vaguely reminiscent things. I'm a lifelong SCUBA diver and Instructor (1975, 1982), and almost all of my diving over the years has been in cool to cold water (RI, CA) requiring a neoprene rubber wetsuit, or in tremendous cold, a dry suit. Now you can make multiple dives in a day in a wetsuit and still be pretty warm, depending on the water temp and some other factors. That's the way a suit works if it fits well. However, I used to dive and teach SCUBA in Narragansett Bay in RI a great deal, usually from about April to November, and even though I had custom formfitting wetsuits, eventually in early Spring or late Fall the students and even I would get cold. So there's at least two solutions, 1) bring very warm jugs of water and pour it down your student's wetsuit just before a dive, or 2) pee in your wetsuit, either before or during a dive. I have a lot of experience with #2! And it feels absolutely like heaven when your pint or more of 98 degree F liquid fills up the groin and chest of your suit! Eventually it will cool off, but it really helps to stay warm! You just need to thoroughly ribs the suit with water afterwards before you go home or your friends think you smell funny (not funny good!).
Okay, time for one old SCUBA joke: what's the dumbest thing you can do while wearing a DRY suit (no water entry, dry clothing underneath)?
Answer: pee in your dry suit (seriously not recommended).
Q: what's the second dumbest thing you can do in a dry suit?
A: tell your friends you peed in your dry suit.
The other vaguely reminiscent thing is that since I love wearing wetsuits or thin latex suits for my rubber kink, it's common to sweat pretty heavily if you're wearing a good deal of rubber. Some find this unpleasant, but I actually enjoy the sweating and water collection under my rubber suits and I'm happy to stay rubberized and wet as long as my imagination or my partner being Domme wants me to. Delicious.