Player communication, increased heart rate, fun!
Stop the balls making it out of bounds.
Running the drill:
The coach starts at the net with a trolley full of balls.
Coach, rolls, tosses, hits, bounces balls anywhere on the court. The on court players must touch the balls before they make it out of bounds.
Off court players are shagging balls.
Run the drill until there are no more balls or for a set period of time. Only needs 1-2mins per pair.