This is the figure-4 carotid restraint hold. While it is an extremely effective submission hold, there are numerous risks of injury to the restrained person due to the nature of the technique. These risks must be weighed in deciding whether or not to use this restraint.
Come up behind opponent, crossing your right forearm over left [or left over right] sliding down over his eyes.
Continue to bring your hands/forearms down so that wrist that’s underneath is resting on the bridge of his nose.
Bring your hands/forearms down a bit more as you pull opponent’s head towards your chest.
Keep the back of his head against your chest as you step back and kneel down on one knee
. . . as you bring the opponent down to the ground.