Correcting posture

In my beginner pitchers (and some advanced) a common problem is posture. We have to have a strong tight core to get the fastest potential God given arm speed. When we cannot find neutral spine alignment and hold it, we slow up. My favorite drill for teaching a pitcher to hold her posture (her stack, shoulders over hips) is to let them pitch downhill. They feel like they will fall over if they lean forward over their stride leg. So naturally they fix their posture and tighten up through the core. Another good magic wand to fix their posture is to have them finish on their tippy-toes when they release. The problem is, we can't finish like this every time because they need to get into a good athletic fielding position after they release. It is still a good drill so they can get the "feel" of the correct posture and hopefully carry it over into the real thing but ending in a good defensive stance on the balls of the toes.