Yep. Quickly grab the brakes like you are doing and then throw the bars over hard as you start to descend, steering into the hill, release the brakes a bit and lean hard into the hill. This will put you 90 degrees from your original route up the hill. Bring the bike up to perpendicular or near that while keeping your balance begin to steer toward the base of the hill, retracing your route. Ride the rear brake a bit to control your descent but avoid locking it up if you can. Viola. Rinse and repeat. It takes a bit of practice. Just find a gentle hill and practice it under mild conditions. It's easier to learn it this way than when you think you are about to die.