The Pale Rider from the top position starts when you are transitioning to the Gangsta Lean.
This technique comes into play when you have the top position and you are transitioning to the Gangsta Lean but your opponent locks their arms around your waist. This makes it very difficult to control their wrist and pin it to the mat for the Gangsta Lean.
So what you can do as demonstrated in the video above is pummel one arm in, Vice Grip your opponents bicep with the other arm, apply pressure and get the tap.
The Vice Grip can be used from a number of positions. You can use it from the Butterfly Guard, Half Guard or as in the Pale Rider. It is surprisingly painful when done correctly.