The pilot of the tailwheel-equipped airplane reported that, during the preflight for a demonstration flight with another pilot, they discussed the nose-over tendencies of the airplane and the need to "stay off the brakes." He added that, during the fourth touch-and-go landing, the second pilot was flying and performed a wheel landing. During the landing roll, the airplane drifted right, and the pilot "came on the rudders to help." Suddenly, the airplane nosed over. The pilot reported that he believed he was responsible for the accident and that either he or the other pilot must have inadvertently applied the brakes. He also believed that he misjudged the second pilot's tailwheel experience. The second pilot reported that, at the time of the accident, he had a tailwheel endorsement and met the recency of experience requirements. He added that, during the landing roll, the airplane was tracking the centerline when "suddenly and unexpectedly" it nosed over. The airplane sustained substantial damage to the right wing lift strut and empennage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.