How to actually successfully choke someone out with the cross collar choke from closed guard. Excerpt from https://www.grapplearts.com/closedguard The Closed Guard System, a step-by-step formula for developing a KILLER closed guard by Jon Thomas!

Two of the keys that Jon demonstrates in this video include getting your first grip in at the right angle, and then genuinely attacking with other attacks (sweeps, armbars, triangle chokes, etc) so that he breaks his defensive arm structure and gives you that opening to sink your second grip into position. I think this approach will allow you to finish a LOT more people with this classic choke.