This drill will help with the right shoulder and right forearm motion and alignment.
Take a ball in your right hand. A nerf ball if indoors. Get into your impact fix position with your right hand below your left. Keeping your left hand still, move your right arm to the top of your backstroke.
While you are there, look at your right hand. The back of the right hand should be parallel to the planeline and your right wrist should be bent but not cocked.
Now throw the ball under the left hand about where a golf ball would be on the ground along the plane line. Pay close attention to the movement of your pivot and right shoulder motion.
The key is to throw just slightly under your left arm without making contact with it.
__________________
Bagger
1-H "Because of questions of all kinds, reams of additional detail must be made available - but separately, and probably endlessly." Homer Kelly