A quick youtube search shows these,
For the traditional wrestlers double leg:
http://www.youtube.com/watch?v=ClG2VGOt60c
For the high crotch:
http://www.youtube.com/watch?v=EZggaJFnY5U
I was taught to elevate the leg & drive before switching grips but that doesn't mean the video is wrong (or my coaches) it's just a slight variation.
I couldn't find a clip for the bull double but I think that one tends to be easier to understand. You get your opponent upright & then hit their belly with your head while pulling up on the backs of their legs. it can be done with a bowing motion or by chanding levels & then standing back up but leaving the head down.

