I used to know an adult baby scene enthusiast. He ran a second hand stuff shop in Burton on Trent.
I'd never met him before I went into his shop and I was looking at some horror VHS tapes he was selling when he walked over and said ..
"Oh, I see you like your horror?"
.. most of the tapes were lame Hollywood like stuff instead of stuff that was once banned in the video nasty years so I made the mistake of saying ..
"I do but I'm more into the hardcore stuff." (meaning video nasties)
So he went into the back of his shop and returned with this non labelled VHS tape and said something like "You might like this.".
I got back home and put the tape to one side assuming it would be something I'd already seen. I was bored one day so I put it on ............
It was people doing anything you can imagine in a sexual context with poo and wee ... this was
years before two girls one cup and the internet and that.
Naturally, my first thought was BLLEEERRGHH

.. my second though was 'ACE!!! .. I've
got to shock my mates with
this!" .. so I did. We were all laughing our heads off although one of my mates confided in me that his girlfriend got aroused by the viewing and then done a bit of 'experimenting' afterwards.
I took the tape back to 'Pokko' (I never did ask him what his real name was) with "Christ. I've never seen anything like that before? .. but cheers anyway." which was when he told me he was into being an adult baby, his nappies being changed and poo and wee kinky stuff. He was completely relaxed telling me about it all ... apparently the
real underground people who actually do this stuff for fun use the terms 'champagne' and 'caviar' to talk about urine and faeces he told me. Lovely.