I have a drill I call "Stability Freeze". Basically you ask the pitcher to freeze (freeze hip and shoulder rotation) just as they release......don't even let the hand/arm follow through....make the hand stop (not passing the midline of the body) just as it did when this pitcher threw into her glove. Note that the back of the hand should be facing third (RHP) to ensure that the pitcher gets IR/Pronation of the forearm and hand. I'll start this drill from a parallel powerline position with a full arm circle and a step at about 25 feet from the catcher. You can progress back in distance and get to a full motion from about 30 feet.