Artemis BJJ (MYGYM Bristol), Can Sönmez, Bristol, UK - 23/11/2016
Secure the crucifix by driving your knee in from the side ride, flaring your knee out, then hooking their arm with your other heel. Drag their arm back and make sure it stays trapped between your legs.
Put the knee nearest their head slightly forward, still controlling their arm. Turn to face their legs, grabbing their ankle to anchor yourself in place, with your head in line with their bum. At this point you will need to switch your legs, so that you can get the leg further away from their head closer to their wrist. Twist your body and swing the leg furthest from their head backwards, still hooking the arm. Do this movement gradually, as that shoulder lock can come on quickly, depending on their flexibility.
Teaching Notes: Dave Jacobs describes this as a shoulder lock, but it invariably becomes an armbar when I do it. I'm not sure exactly what he's doing different, but I'll check that carefully for next time. It still works as an armbar, but meh, would be good to get the shoulder lock properly. Jacobs puts his non-lifting leg by their shoulder, which might explain it: for the armbar, you need to put it up higher. Also, I keep emphasising that if you can't get this, you've still got all the other stuff, from clock chokes to reverse omoplatas. :)