Drops are breakdancing techniques that allow b-boys to transition down to the floor and begin performing downrock.
A wide variety of other movements can serve the same purpose, and others such as the kip-up can work in reverse, moving the breaker up from the floor.
The left foot kicks quickly forward so that it slams into the back of the right knee in a "figure-four" position.
Ideally, unseen by observers, the left foot actually sticks out just to the right of the collapsing knee, and the toes should be pulled up hard.
By the time the right leg has swung around to point directly ahead, the left knee should be fully bent and the hands are ready to hit the floor and bear the body's weight.