Mention in advance that they should play around and then set up a support and rebound.
Also mention that the support stays until a follow-through or shot comes. Because if the ball is spent for a shot and the defender gets to it in time then the ball can be played back on the support.
The support remains until the defender gets in front of the support to avoid the returning pass
Thus, the defenders must learn that after a spent pass is returned immediately in front of the support.