I knew as a little boy i liked being wet and messy in my undies. It felt right and natural even though i hid it and cleaned myself up as best i could. Started to hide diapers from friends houses while playing their and put them on fill them up when I could and it went from there. I think the pleasure of being wet and messy is in all of us as little kids but how we deal with it as we grow is where it takes us as it did for me.