What is involved to dog leg?

just curious what all is involved to dog leg like this guy

http://www.teampneumatic.com/vid/vid-16.avi

I have plans to bag the back of my 95 sonoma but after seeing that video i really want to be able to pull off a dog leg like that. Kevin (555) told me that its done with cylinders. I know about bag setups and how it all works and everything but im not very familiar with cylinders. Could you guys post some pics of cylinder setups or shoot me some info on how i could accomplish this?

thanks