Swim close to the lane rope and stay on the same side of the lane (can’t do this when circle swimming). When the hand enters the water reach up to grab the bottom of the lane rope (reach up from underwater). Once you have a firm grasp on one of the lane rope rings pull down keeping your body as close to the rope as you can. The rope should be skimming by your armpit. Still take a stroke with the other arm like normal. Pulling on the lane rope teaches you what it feels like to propel your body past a fixed object (in this case your hand) and it helps establish good underwater mechanics for the backstroke pull. Proper backstroke pulls require shoulder flexibility that the average triathlete will not have, but you will loosen up the more backstroke you do. This drill should be more fun than others because pulling on the lane rope is considered cheating, but for this drill you’re supposed to cheat.