The flight instructor was providing tailwheel instruction to a pilot who was going to purchase the accident airplane. They had completed 10.7 hours and 56 landings. Because the pilot planned to depart the following morning with the current airplane owner, the flight instructor said that he felt pressure to complete the pilot’s training that day. While practicing three point landings, the wind was gusting to 19 knots. After touchdown, the airplane began tracking to the right. The flight instructor stated that he was guarding the controls closely but delayed assuming control of the airplane to let the pilot correct the situation on his own. The airplane then swerved to the right, and the flight instructor was unable to regain directional control despite full application of left rudder and brake. When the airplane ran off the runway, the airplane’s left wing and aft fuselage were damaged. The flight instructor reported no preimpact mechanical malfunctions or failures that would have precluded normal operation.