The urge to wear diapers for many of us could be for the reason of an event during childhood or perhaps a memory. I think the reason for me is memory. The farthest back memory that I know is a direct memory (not a pseudo-memory created by desire) was back when I was a literal baby, still wearing (and using) the diapers placed on me. This memory has played out the same way since I was about 5 or 6 when I really started to think about diapers as a thing at all, probably from seeing diapers stacked at the back of a kindergarten class, it probably got me thinking, and uncovering that memory.
Note: Before I remembered this memory, I had not been in my grandmothers house any other time in recognizable memory. And the house is exactly the same as it was back then as she still lives there. More specifically the pillar and couch dividing the living room and the kitchen.
The memory plays as a diaper change at my grandmothers house. Its all visual, no audio. But what I do know is I was able to walk. At least 1 year old. But I was with the grandmother on my fathers side, which was after the trip to the US my mother made (which involved leaving my father). So I was at least 1 & 1/2, and after the court case was settled which was visiting my father every 2 weeks on count which means I was at least 2.
I don't think I was able to walk at 1/2 a year old.
During the walking scene, my eyes always gravitated towards the ground, but more towards the diaper I was wearing, perhaps I was trying to compose a proper thought about the diaper, or I was just focusing alot on walking for whichever reason.
That memory and the visual gravitation towards the diaper might not be what makes the desire to wear diapers as it is today, but perhaps the fact that its the memory that sticks the farthest back, first accessible memory as of today. With no further memories that I know of until at least 1/2 a year later when we moved to a small town in Ontario, Canada.
It's a far-fetched idea, but its an idea none-the-less.
I like to uncover memories as a whole, not just ones like this, but memories as a whole as I can piece together my own history, "pausing" and focusing on the surroundings to figure out what time it is in my past, and where I could possibly be (I've been everywhere at some point or another).