Ahh but you are not truely skanking until you add the kicking element.

Step one - stick out arms, either in tree hugger technique as above or slightly out and relaxed, bent at the elbow (so your elbows are a few inches off your body)
Step II - bend slightly at the hip
Step 3 - sway side to side while keeping feet still.
Step D- Kick. Turn the sway into more of a swing and kick on the same side. For instance, when going right, kick with your right leg out. Magnitude of the kick is dependant on style, and speed of music and amount of space available. Anything from a simple kick that barely passes the other foot to a full waist high kick with a recovery is acceptable.

Part 4 - repeat