There's abseiling and there's absailing, didn't you know? When you absail you attach a sail to your back and kind of free-fall tied to a pungee cord (a bungee that hasn't been washed for yonks) and you kind of contract your abdomen muscels to control that sail on your back. It's a new sport, very popular in Russia, about to become a massive hit in the West - it's a combination of abseiling, hang gliding, bungee jumping and yachting. I challange you to try it!