You just take a knife and a potato, and you put them together and just twirl the potato around while you cut into the skin just softly in a circular motion. Then you take it and you cook it like you normally would.
Now, by cooking the skin with the potato, you actually infuse the potato with more flavor because most of the flavor of the potato is actually in the skin, so you get more potatoey mash. And once you've cooked it, you can just pull the skin off just like this. And it's so much more efficient; you don't waste any potato. And it's much quicker than peeling it.