While swimming in water or lava, approach a ledge that would cause Link to jump out if you were to push against it. Tap the circle pad briefly toward the ledge; this will store the animation of jumping out. The next time you push against any wall while swimming, Link will jump out. This can be used to get up to ledges that are normally unreachable by swimming.
Note that taking damage or pressing A to boost after the animation is stored will get rid of the storage.