Rotational Twists
A good exercise for skiers, keep your body facing forward throughout the movement, all the twisting come from your waist and lower body.
With your feet shoulder width apart, and body vertical, make small jumping movements to your left, then your center, then to your right, finally finishing back at the center again.
You may wish to work with your feet flat on the floor with each jump, or on the balls of your feet.
As you become adapted to this movement, you can progress by jumping left to right and vice versa without having to jump in the center.
Focus the movement on achieving speed with each jump.