The pilot, with one passenger on-board the airplane, was to practice maneuvers with the airplane. The pilot performed "lazy 8's, circles around-a-point, S-turns, and low-flight." While doing slow flight at full power and flaps deployed, the aircraft's right wing dropped; the pilot tried to correct the problem by lowering the nose and applying aileron and rudder. However, the pilot reported that the aircraft started to spin, and oscillate left-to-right. The pilot was not able to fully recover the aircraft before impacting the surface of a lake. Both the passenger and pilot were able to open the aircraft's door and exit the craft.