The North South Arm Bar is another great submission from this position. In the video above Braulio Estima, BJJ World Champion and ADCC Champion starts the technique from Side Mount.
From NS with Head & Arm control you can still work this technique. You transfer your arm that is under his neck to trap his elbow. After trapping his elbow you cut your forearm deep under his arm palm facing up until you get your wrist to his armpit.
