Have you ever wet yourself on purpose?

Yep. Started in my teens, and still doing it.

my 8 year old brother loves to wet his bed for fun, and also likes to pee his undies

Loads of times -it's a constant source of pleasure for me ;-)

Many many times both my bed and my pants.

Guess ☺

Yes! Started in my teens to see what it felt like,an enjoyed the feeling so much,I just continued to do it in private forever.