In this video I show a transition from the North/South Choke to the Paper Cutter. I also provide a few tips on how to finish this technique.
Often when I see this move performed it crushes the windpipe. While this can be a bi product of doing the move, it should be a strangle first (blood choke). Make sure to understand that the collar is one piece of cloth and the collar grip under the shoulder has the ability to tighten the choke as well.
Make sure your hips are turned towards your opponents and your only on one cheek. The pathway around the head is very important and adds a lot to the choke. Check it out and try it both ways during drilling and you will see there is a clearly better choke.