I know that some who are into wetting and nappies started doing it as adults, and were introduced to it by their partner. They start out doing it to please someone else, and find themselves hooked. Other readers though, can trace their interests back to the way they were treated as children, and this is especially so for bedwetters. Lots of kids continue to wet their beds right into their early teens, and some are even made to wear nappies. Around puberty they start to realise that wetting their bed or nappy is pleasurable, and it often becomes something sexual.
Many readers recall waking up in a wet nappy as a young teenager, and masturbating in it.
Mothers can easily affect the attitude to wetting, and some make a big fuss over their kids when they have an accident, and give them lots of attention. It's not surprising that a few start to do it on purpose. There are a huge number of celebrities who have admitted to having accidents, but none would ever admit to getting sexual enjoyment from it. Our favourite celebrity is the American actress Suzanne Somers, who wet her bed every night until she was 14 and even did it on her honeymoon. There was an interview with Howard stern where he dragged all the details out of her, and even said he found the idea of her lying on the wet sheets to be a turn-on.