the hang on method always worked for me on dirt and my old S3. If you can help it, you of course keep your feet on the pegs but that can be easier said than done. Head shake, tank slap, or whatever you want to call it can get pretty f****** violent. It's also important not to tense up when hanging on, have a firm grip and let the bike do it's thing. Trying to muscle it can have a negative effect if your body motion starts aiding the wobble, especially with wider bars (it's like a wrestler using his opponent's body weight to his advantage). Essentially what happens is you create a feedback loop. If you see someone get this in a race and get bucked off the bike, more often than not the bike will correct itself and stay up until it hits something.
Getting on the gas isn't a bad option and totally cutting the throttle can have a negative effect by slowing the back tire so much that it skips, causing the bike to high-side. Hitting the brake can have the same effect. Whether you ease off the throttle or get on it be easy with it.
As with anything, the correct thing to do is situational dependent. If you're going through a corner and get head shake, then you should accelerate as smoothly as possible through the turn. Decelerating will cause the bike to want to stand up and head for the outside edge of the corner. If you're on a straight road with plenty of room I would probably decelerate slowly and remain calm until it stops.
2 years ago I compression fractured two vertebrae because of head shake, well it was mostly my fault. Story: On the S3, passing in a no passing zone (plenty of room for how quick that bike was), on the gas on a bumpy road, the front was light, hit a bump, and suddenly head shake from ******. I eased off the throttle and held on and it began to straighten out but I still had the car to get past before I ran out of room so I got on the throttle again and the same thing happened. With the blind corner approaching fast and the bike wobbling like a 10 yr old with A.D.D. and on crack, I picked the lesser of three evils (1. attempt to ride it out and hope nothing was coming around the corner 2. not be able to ride it out and get run over by the car I was passing 3. take my chances with the berm) and 150 ft. through the air, a totaled S3, and a broken back later, the ambulance was on it's way. I still pay for that accident every day but at least I'm alive and riding again.
The point of that story is that it has been my experience that getting on the gas will not always save you. I am, however, a true believer in Gary Bailey's philosophy of "when in doubt, gas it".
I hope this helps some of you, and if anyone has any differing opinions I would be more than happy to discuss them as there seem to be many different ideas of how to handle this problem.
