A diaper not just a symbol of childhood more than that though, it is a symbol of what is contained in that diaper. When you have a dream about a diaper you are thinking about all of the things that a diaper contains, and surprise, sometimes they aren’t so nice or so great.
If you have a dream about a diaper then this means that you are thinking about all of the baggage you carry around with you and how hard it is for others to deal with that baggage as well. A child does one thing with a diaper, poop or pee in it. Then an adult is the one that has to take it off, wipe them, throw away the old one after tying it up to make sure the stench doesn’t escape, then you put on a new one. You are thinking about all of the baggage you carry with you when you have a dream like this and are trying to see if there is a way that you can get around things in the future so that you don’t have to think about it anymore.
If there is a strong opposite to a dream about diarrhea it is a dream about a diaper. While diarrhea symbolizes the inability of you to keep your crap to yourself, the diaper symbolizes the precision with which you are able to keep your feelings to yourself so as not to bother anyone else. You let them out on your own time and this requires discipline. You should be applauded for it.