The following description exists for REFERENCE. It is NOT intended as INSTRUCTIONAL
How It Is Done
The Attacker gets the Defender's head between their thighs while placing the Attacker's own ankle behind the Attacker's opposite knee. The Attacker then closes/traps their ankle behind that knee, creating a "number four" with their legs around the Defender's head.
How To Escape
The Defender's limbs are all free to try and effect an escape.