If I remember, his thigh's are fiberglass.
What I would do, is trim any excess fiberglass thats not essential to the overall look and or shape. After that, get a sanding sponge and wet sand the edges, as well as the whole fiberglass surface, until you get the surface nice and smooth. Then take primer and spray the pieces in that, so it will reveal spots that are not totally smooth, ect. wetsand it again, until baby butt smooth. The smoother the surface, the better results from the rub and buff.
After that, you will start to apply the rub and buff paint. This is where it gets tricky. Take a little bit, like let a little bit of the paing pop out and put that on your forefinger. Rub it on in small circles over an area and even out the paint until its even. You can either use the palm of your hand, or cloth material like an old white t-shirt, or shoe polishing cloth, and buff it furiously, applying a good amount of preasure.
Keep repeating this and you should get a good shine going. DO NOT spray a clearcoat on it, because it will dull out and will look like silver spray paint.
Also, after touching the r&b paint, DO NOT touch anything unless you intend to paint it silver, trust me. Good luck dude!
-tubachris