egg on your face

To be embarrassed after being caught doing something wrong. Among the possible origins are being red in the face about being told you left a smear of yolk around your mouth after breakfast or the humiliation that performers suffer when unhappy audiences pelt them with raw eggs. Closer to the mark is a barnyard explanation: farm dogs that develop the taste for raw eggs and break into the henhouse for a treat have that hang-dog look when confronted by their angry owners.