Defensive jocking is when the defender contains the attacker to find the right time to steal the ball.
In the first jocking exercise, the attacker is shielding the ball. Two players play one v one, the attacker is holding the ball, the defender waits until the moment where they can steal it.
Key factors to jocking if the attacker is shielding the ball. Be close enough so that you can touch the attacker. Give yourself an angle, not square on. Bad angle, good angle. You want to be able to stay low and change directions quickly.
In this second exercise, the attacker is dribbling towards the defender in a zig zag pattern. The defender wants to stay goal side of the ball and change directions quickly when the attacker cuts. Waiting for the moment where the attacker hits the ball a little bit too far in front of them. At this point, they can go for the steal.
To be a top player, you have to be able to play on both sides of the ball and jocking will really help your defending.