Bring 6 – 8 players together under the basket. Have all the players raise their hands over their heads. Instruct the players to stay in this position until the shot comes off the rim and then secure the rebound. Huddled up in this way many players will tip the ball up, over and over again without securing it, or grab the ball and lose it again. Repeat this several times to demonstrate the inconsistency. Then review the basics of boxing out with all of the players and emphasize the need to create space under the basket to improve the chances of securing the rebound. Start with making contact, pivoting into position, holding the position, releasing to the ball with a block and tuck technique, chinning the ball and pivoting away from pressure. Start the drill again and insist on proper rebounding technique.

See- REBOUND LIKE A PRO  PGC https://youtu.be/Gw_UGI1upN4