Set up a ball exactly as you would for a flat chest press, with only your head, neck, and shoulder blades in contact with the ball. Then do a standard fly, making sure you can see your upper arms at the bottom of the range of motion.
Set up a ball exactly as you would for a flat chest press, with only your head, neck, and shoulder blades in contact with the ball. Then do a standard fly, making sure you can see your upper arms at the bottom of the range of motion.