What is the ritual for Pinky Swearing?

I just did a pinky swear the other day, and it got me thinking just how bizarre it was. There doesn’t seem to be any formal info on it other than some wiki page someone wrote up. So, what I want to know is, how do you pinky swear? Are their rules to it? For me I always intertwined pinkies, one of the participants states what the promise is, and then we both kiss our thumbs to seal the deal. And of course, a pinky swear cannot be broken!!!! Is it different from anyone else? Or any one have interesting pinky swear stories?