I don't know how I thought to try this, but it helps distract me from my body's urge to become one tight muscle when I'm riding downhill. It's similar to the technique that equestrians use during shows.
I don't actually "bounce". Rather, I just raise my body up a slight bit and then back down. Then I continue my downhill for a beat and then repeat the up and down. I continue to do this till I reach the bottom of the hill. This lessens my focus on the paralyzing fear.
Anyone watching me wouldn't even notice. The fear is initiated by the mind and transfers to the body. This simple activity works for me. Otherwise, I'm thinking only about crashing and losing skin. I had a horrible wreck in 2005 and I know how much it hurts. I still have good days and bad days with descending, but I can decrease the panic to a tolerable level so I can enjoy my rides.
Hope this helps. Barb