The "rush" or "streak" is not a supersticious idea of Brunson's, it has to do with how the other players are viewing you. You have to make the most of your opportunities, as they may come around seldomly, so, if you showdown three or four good hands in a row, then your opponents view of you will be conducive to a rush. You go with it as long as you can. Then you go back to playing your hands, and not the opponents perceptions.