Rotate your upper body as you're locking on. You don't need much.
Rotate your shoulders in direction of the spin; look over your right shoulder with your ass pointing towards the end of the box/rail. As you near the end of the feature give yourself a little pop and turn your head & shoulders back to the left so your left shoulder is facing forward down-hill. This rotation should pull your legs around to your normal forward stance.
Great advice D. Also, if you want to come out regular, be sure to use plenty of counter rotation (explained in the video below)
Thanks for the plug Alec!