Some of us remember seeing the renowned "Side Bar Defense" in action when we were younger. Some of you may have seen a brief demo during LJT's Best Man speech at SB's wedding. For those of you somehow completely unfamiliar with it, what happens is that when someone (say, your older brother?) starts attacking you, your best maneuver is to get down on the ground and keep your feet and legs between your face and your opponent.
In other words, something like this: (skip to about the 3:50 mark)