Just came across this 40 minute ling podgast on huffington post. It actually does a good job explaining what fetishes are, then goes into a diaper fetish.
https://m.huffpost.com/us/entry/us_55f189e9e4b002d5c0783e64
https://m.huffpost.com/us/entry/us_55f189e9e4b002d5c0783e64