I have been tinkering around with a similar submission--albeit with a different set up--for the past few months. Until recently, I didn't know what the finish was called and I was winging it when it came to the details. Yet, I nevertheless had some luck with the technique. So, upon digging around the interwebs a bit deeper, I found a very cool leg lock that isn't as hard to enter into as one might assume. It's called the cloverleaf, the Texas cloverleaf, the double Achilles lock, etc. At a later date, I will discuss some of the various ways I have experimented with when it comes to setting up the "laced leg" position that serves as the starting point for the technique. For now, here are a few videos which show different set ups, details, finishes, etc. As always, watch, learn, and go train!
The videos are below the fold!