Re: Ukemi and Koshinage
Physics will help you to learn sutemi.
1. Just like the guy who lays on a bed of spikes; surface area reduces pressure (PSI). I do not encourage students to learn to break fall by touching feet (or hands) first. touching feet (or hands) first will place a great amount of pressure into those extremities, which may result in bruising, jarring, or breaking bones. Your backside and back provide the greatest area over which to dispurse your energy.
2. It sounds like you are over-rotating in your sutemi. Ron posted a helpful tip for over rotation, by controlling your body rotation. You can always expand your body and slow the rotation process; it is more difficult to start in a slow rotation and speed up. You will force your head and shoulders through the throw quickly by looking at your partner. You can better control the speed of your torso and legs as they go they through the rotation once your head and shoulders pass first.