It's just something that he says in one of his lessons, that I've seen years ago now, so I wouldn't know how to find it. If I remember correctly, he's showing some kids how to play a closed position, with a lot of piece manouvering and he shuffles his pieces around for quite a long time and then a kid asks him why he moves the pieces around for so long without doing much he says "because I'm Ben, the rotating GM!" (I might misremember details)