This position has so many names that it is hard to keep track, but I’m going to settle on the 10th Planet Jiu Jitsu terminology and go with Honey Hole. 
For the past few classes, I have been teaching the honey hole ever since I worked a particular setup from the butterfly guard that had my students in awe. This particular finish to the honey hole I haven’t seen taught online. I think I learned this from Dean Lister when he did a leg lock seminar at my school, the Freestyle Fighting Academy in Miami, FL.
Anyhow, this finish is surprisingly effective, as it applies a strong inverted toe hold that is devastating on the knee. Check it out and let me know how it works for you!