I sometimes end up wearing a pair of briefs over my diaper when I wear one, which is 80% of the time to bed. It almost depends (haha, never gets old) on the kind of diaper I'm wearing, where plastic-backed ones I won't bother while cloth-backed is usually with some form of covering.
For me, during the day, I wear my white briefs or my boxer briefs over them to help hold them up. At night, I don't wear anything over them, I just sleep with just a diaper on and nothing else. Today since I am home, I just pulled a pair of jeans over my diaper.
The reason I wear something over my diaper during the day is to help hold it up. After I wet it a few times, it starts getting heavy and druppy.
When I am diapered I always wear a pair of plastic pants over them. I wear regular pull on plastic pants from Comco with my night time cloth diapers and terry lined ones from Babykins when going out wearing a disposable.
I usually only wear diapers when I am downstairs (I live in a split level home) in my room by myself at night. I usually don't wear anything over them to keep from sweating as I prefer the plastic backed variety. I do have a onesie I occasionally wear, but when I do wear diapers, it's usually a Spongebob T-Shirt (the most child-like shirts I have) and the diaper.
I was going to bring up this very question, but wasn't sure if it would be too personal for the folks on this board, so I didn't bother. I guess if we're all DLs,TBs, and ABs, its ok to talk about these kinds of things that we try so hard to keep hidden from the outside world.