Goofy Gymnastics (1949)
Under his yellow caveman suit, Goofy wears underwear that is frequently shown throughout the cartoon while he is exercising. While trying to lift weights, Goofy gets his hands and feet trapped by the weights and lifts up his bottom moving it back and forth. His caveman suit falls toward to show his underwear. Then as Goofy rolls on the weights like a wheel, his caveman suit falls over his head leaving a full exposure of his underwear.
Goofy flies out of one building and catches the window sill of anther building disturbing a woman.