Here's my current script which I've thankfully never had to use:
Your ordinary adult diaper stash is discovered:
'Some family friends who came to visit me were bringing their elderly relative and asked me to track down a few supplies. These are left over, not quite sure what to do with them.'
Your baby print diapers stash is discovered:
'A mate of mine wanted to dress up as a baby for Halloween, so needed to order large novelty diapers. Unfortunately he was locked out of his PayPal, so asked me to order them. (If they are unopened) Unfortunately they didn't turn up till after Halloween, so not quite sure what to do with them. (If opened) He got changed here, but didn't take the rest.'
You are discovered wearing ordinary diapers:
'I've picked up this rare parasite. Generally I'm ok but doctor says I can't be too careful.'
You are discovered wearing print diapers:
A joke? A bet? Hidden camera prank? To be honest, in this scenario you are probably screwed.