For many, the north south choke is one of the most frustrating movements to learn in the art. We talk a bit about some common issues surrounding the NS choke, why it fails for many people, so helpful troubleshoots, and some famous match examples of the technique being used. 
Some great live-use match examples are: 

Marcelo Garcia vs Pablo Popovitch (ADCC 2007) - https://youtu.be/JozmB8JZAFI

Marcelo Garcia vs Francisco Mendes (Worlds 2010) - https://youtu.be/bMUduVl7_Xs

Josh Hinger vs Marcos Tinoco (NoGi Worlds 2018) - https://youtu.be/RQizNfEydi4

Darragh O'Connaill vs Richie Martinez  (EBI 3) - https://youtu.be/SzYSWBWq3W0

Garry Tonon vs Daniel ? (AGC 2014) - https://youtu.be/4KuZGlqGhxo

Buchecha vs Anderson Silva (ONE FC 2021) - https://youtu.be/Gi6wJnolzh8