What it is: Climbing onto the first layer of a tower (Where people normally stand to cast onto the attacking faction) while in a vehicle (Not mount, the WG Vehicles).
How to: Make your vehicle. Drive to the tower you want to climb. There will be a little platform that juts out like a pennisula on the front of it (Its the 'front' where players will jump off to leave the tower on the bottom. They usually hide behind the slightly higher walls that provide LoS that are right beside the platform you want to wiggle onto). Go left to right when up against the tower and you will simply wiggle your way up, and will be able to turn around and use your vehicles abilities all you want. If you are simply going slower when riding the wall, you're almost in the right spot. Try and hit a 'corner' and wiggle, you'll easily make it up.
Why: The pushback knocks players all the way off the cliff most of the time and it still damages buildings.
Also: I'm describing as best I can because I can't provide SS until tomorrow. But until then. enjoy =)
Picture: http://s291.photobucket.com/albums/l...=1259697511359
The black circles are where you 'wiggle' to get up, and you will find you just seem to float almost up the side when you do. Then you just turn onto the platform and spam your siege abilities until you knock everyone off and the tower gets destroyed.