Marcelo provides some helpful insight on the finishing details behind his North/South Choke: A major component behind success with the North/South-Choke is a matter of attacking the neck with a clean entry; whenever your opponent has their hands preoccupied and their chin open, you can slide your chest away from the pin and drop down into the attack. Wrap your arm around their neck with the aim of landing flush alongside their neck with your lat-muscle/rib-cage. Pinch your elbow inwards medially, and hold your opponent's jaw open vertically with your arm-pit as you continue to pin them flat onto their back. Connect your hands together underneath their back with a Gable-Grip (i.e. thumbless, palm-to-palm), and throttle by shrugging your shoulder/delt forward onto the their throat. After intiating your attack, if you notice that your opponent is properly defended, quickly reset away and take pressure off of their head and neck. Your opponent may underestimate the danger of a follow-up attempt; don't let them onto your intention of insistance with the choke by squeezing inefficiently and/or prematurely. Reconsolidate your pin all the while hunting for another opportunity to cleanily drop back down again for their neck.