Here is a quick Pilates Suspension Method (PSM) Class that uses the small ball. You can do this entire class without the ball or substitute a throw pillow or stability cushion and still get a great class. The ball I am using is 8-9 inches in diameter and squishy.
If this is your first PSM class, check out my Tutorial, How to Mount and Adjust your TRX (LINK), before starting this class so you can move quickly and confidently through the transitions.