Think box then play box: get reactive over the ball
The instructor describes the think box and play box: in the think box you think about your swing and try to get a feel, but once you move to the play box, which is over the ball, you want to get more reactive. He counts players over the ball ('one and two and go') so they find their own internal rhythm, noting that a rhythmical routine produces a rhythmical swing.
Channel: Mark Immelman
Watch official source at 30:24