Here is another great training drill you can do on the Bosu ball, this is one of my favorites. It's a triceps press with a medicine ball.
The weight of the medicine ball is continually trying to bring you out of balance, and because it is right over your head and then directly behind it, to me it seems to closely simulate the feeling of getting thrown into the back seat at the bottom half of a turn, and having to fight out of it.
Do this exercise with your free leg in a variety of positions: the one ski skiing position, leg out in front, leg to the side, leg behind. Make sure your shoulders stay square, and fight to stay stable and in balance so you can have good form for your triceps!