This is a beginning exercise for developing balance and stability for further tossing and throwing exercises.
Using a 5- to 15-pound ball, stand with feet approximately shoulder-width apart and your back to the partner. Bend your feet a little. Hold your arms long, chest out, and hips back.
Pass the ball back and forth over the head and between the legs while maintaining a chest-out posture and full-foot contact stability.
After performing sets of 10 to 15 repetitions, switch from receiving over (or under) to passing.