I know what some people might be thinking, but this is a variant on the cliche- I don't actually have any memories of ever wetting or messing my diaper as a baby.
What I do remember, however, is a brief instance of my sitting down on a newly-filled diaper and feeling the 'squidge'.
I have something of a love-hate relationship with pooping. I'll do it- either in diaper or pants- but then I can't resist just sitting down heavily after I've done the dirty deed. This is where the 'hate' comes in- the long and torturous cleanup required.
Would it be jumping to conclusions to correlate the irresistable urge to do this with that earliest memory?