Superswimming works like this: You activate "storage" which you can get from either cancel your wind waker three frames from hitting the ground or taking it out at the same frame your forest water expires. When you have gotten storage, and you take out the wind waker again, you get in the wind waker graphics, but you are still able to move like normal. When you get in the water in this graphics and put the controller stick up, Link will change his direction every single frame, since the camera always faces Link. This builds up speed and when you release your controller stick, Link moves away backwards in the current direction.