When I was about fourteen my friend was spending the night and we decided to try the warm water trick on my older brother. I slowly crept into his bedroom and ever so carefully set a big metal bowl of warm water on the night stand next to his bed. Moving in excruciating slow motion I picked up his arm and moved it, milimeter by milimeter, toward the bowl. Finally his hand was positioned directly over the water. I slowly lowered it in and when his wrist had reached the edge of the bowl I let go.
Abruptly the weight of his arm flipped the entire bowl of water, emptying its contents all over his head and torso, and soaking his bed. Oh my god, how I ran.