As regards to the making-someone-pee-hand thing. I was told it was the wrist, the pulse point, that had to be immersed in the water. By someone who said they'd done it.
And no Scargy, I never found out what made me pee that night but it did enable me to tell this anecdote:
I was at a friends party that had adults and children, most of the kids playing in the bedrooms.
I'm sitting in the kitchen next to the snacks when out of the toilet next door comes a mother and her 4yr old daughter. The child sounds like she's really upset and crying but I notice there are no real tears, however there is real anguish in her voice.
The mother is saying something that is obviously a continuation of an earlier conversation "But you must understand, mummy's not angry because you wet yourself; it's because you lied to mummy"(It transpired that a wet patch had been found in the kids play room, when asked the child denied it but a little later the mother found her daughter was wearing sodden knickers)
The mother, thinking she was being reasonable and explaining very clearly to the child exactly where her naughtiness lay, did so in front of me and other guests. As far as I could see, all the child could hear was her mother telling everyone she'd wet the floor (tatami mat actually, this happened in Tokyo) Doubling up on the shame she had already felt which is why she hadn't owned up in the first place.
So, the mother is being gentle but firm in her explanation, the daughter is doing her primal wailing when I leant forward and whispered in her ear "I'll tell you a secret, sometimes even grown-ups wet themselves"
The child went dead silent, looked quizzical for a moment, and was fine.