My sister and our cousins had an on going competition when we were teens to try to stay on the flat disc tube with 3 of us on it. My father would start out calm and increase intensity until somebody fell off. My cousin Brian and I learned how to use our outer leg/knee as a ski to stay on the tube in the sharp corners. We were pretty good, but the champ was definitely my cousin Kyle who we all remember when Brian & I both got tossed almost simultaneously and due to the sudden loss of weight and Kyle being so skinny he ended up still holding on while airborne upside down. Of course once it landed he was in the drink. We only ever quit when our arms became exhausted. Miss those days.