Julia Taft Bayne, who babysat for the Lincolns, later told stories of Tad perched on the back of his father’s chair while Willie sat on one of the president’s knees for a story — usually a melodramatic tale of hunters and settlers attacked by Indians.

Bayne once opened a door to find the president flat on the floor laughing, with his sons and their playmates trying to hold him down.

Source: Lincoln: America’s Greatest President at 200