On that bright sunny day, with that bright colorful ball, you need to look bright with bright green tee of yours. Pose against the camera, as if you bother the least. Your reluctant self should be your style statement of the day.
Drop the ball casually, but remember to carry the body language that shows it an accidental drop. Doesn’t really matter if you forget to wear pants, just bend enough to cover the essentials.
Once you are bend the right angle, with one hand supporting the ball and another supporting you… Look up. Give a careless smile to the shutterbugs. They are waiting long enough to have you, your look, your smile and the ball all in one frame.
You can open your mouth bit more, but if you ask me personally.. thats not really needed.
Finally switch to the agony aunt look as if those cheesy photographers have no right to enter your private play room. No matter how happy you are feeling, don’t smile.Maintain that look and exit.