I learned this move in the section in my library where Henry showed escapes from
half a dozen common chokes. Inside the opponent's guard, the Push-and-Pull(PnP)
choke was taught as a way to counter his cross-collar choke(CCC). By itself, it
could be used to open the guard.
To execute, I grab my opponent's lapel a few inches from his chin with the
choking hand _over_ his same-side arm, wrap the collar around his neck, and
push. My other hand grabs the second lapel slightly deeper than the first and
pull. The first hand goes across his throat so that he can't pull from the same
side horizontally and can hide behind the second lapel. When the pressure from
my arms is not enough, I can jump up on my toes and put my bodyweight behind the
straightened choking arm. The situation looks scarier than it really is.
The past week, I successfully executed the PnP in the guard four times sparring in
my BJJ school. Phil tapped, George was saved by the bell, and big Ed was saved by
his long torso. Only Pablo the champ countered with the right move, i.e., uncrossing
his legs and pushing me away with his feet. In every case, I was able to foil my
opponent's attempt of a CCC.
It was just like in some WuXia novel!