Ooh ooh, I want to try..I dont know about this site really, but uh..If I wanted to torture one..
Strip them, except for small bits of cloth over their "naughty" bits. (Moreso if they happen to be female..although I'd feel bad about doing this to a girl)
Now pour burning hot water over their heads, slowly. Not so slow that it's just like..a little drip though. Make this automated somehow..with a continually filling bucket..Like one of those Jap. bamboo pole-things.
After you warm them up, change the water to freezing cold, and then back to an incredibly hot one after they're used to the water.
Now change it up a bit, slide soap around their eyes, and slide a sharp blade around their body throughout the process..As long as they're not a massochist/BDSM/S&M Lover..You know, it'll be so incredibly painful..I could think of some more painful things, or lethal, but this is torture!