In this video I show one of my highest percentage passes for the Open Guard, the Samurai Pass.
Actually this has been ridiculously high percentage for me. Partially because people don't expect you to sit down. This is my go to pass for Spider Guard and a lot of Open Guard variations. Please try it before judging !
I labeled this pass the Samurai Pass because you live and die by it's success or failure. There is no room in this pass for half commitment as you have to basically lay down.
If this goes bad, it goes really bad. With that being said, I've actually never had this go poorly. When you sit at 90 degrees and your knee is placed correctly with a good stretch, this move is nearly impossible to stop.
The counter to this move will be them stopping you before you get to the seated position or preventing you from angling out to 90 degrees. I highly recommend trying this out and playing with it.
Realize that when you sit, you are probably going to be giving up an advantage and you're risking them being able to stand up and get 2 points. Do not let them stand up without you, yourself standing up.