I am told that the Bike Medic program in Houston puts all of their trainees through a "How to fall" course. These guys have to ride in where ambulances can't go, they climb steps in cities on bikes, they cruise into ravines that are very steep and wooded. I am sure there are techniques to reduce the chances of pain or injury after a fall, I would think that the primary thing would be to spread the impact out over as large an area as possible. Don't throw your hand out to catch yourself, just ball yourself up as much as possible when you go over. Easier said than done. That kind of falling takes practice. Got an old mattress you can throw out in the back yard?