My first and only memory of wearing a diaper was a #2 incident, just my luck.
I have celiac disease (an autoimmune disorder and allergy to gluten) that went undiagnosed until my late teens. Because of this, I struggled tremendously with bowl movements as a young child. I would be constipated for days or even weeks and no amount of potty time helped. My mom would bring in books and toys and a step stool to keep me busy while I sat alone on the toilet- but going to the bathroom HURT- and I avoided it at all costs. And it got really lonely in there all by myself! I was bored and I was uncomfortable.
I remember vaguely my mother rummaging through the bathroom looking for a spare diaper (or to check if we even had one). I don't remember being changed into it. I -DO- remember sitting at the dinnertable with my older brother and sister giggling at me.. and minutes into my meal, the excruciating urge to go to the bathroom- no matter how painful- swept over me. I remember running into the living room, grabbing a pillow to hug and hold onto while I had the biggest mess my body could endure making.
I don't remember being changed out of the diaper or even returning to the kitchen. I just remember feeling a lot better... and I certainly won't forget the embarrassment from being teased for needing a diaper! No less my very immediate use of it.