Players dig the ball, set up their position and then underhand pass sideways to their partner.
Before the second underhand pass is possible players must rotate their torso and then rotate again while passing.
To keep players on their toes and encourage quick thinking players may alternately 'dig and pass sideways' or 'dig sideways and pass'.
After each dig player must make few quick bent knees steps to establish a stable position and pass the ball. This drill improve coordination, quick technique execution and also the ability to adapt your body position.
New hitters rarely miss because of their arm. They miss because of their feet. Build a reliable approach, then time it with your setter.
When your hitter gets stuffed, five teammates standing and watching is how you lose the point. Good attack coverage turns a blocked ball into a second swing.
Coaches spend hours correcting arms in serve receive when the real fault is almost always the feet. Fix the movement and the platform fixes itself.