2011-05-08
Explanation
This comic plays on the idea that certain playful behaviors are socially acceptable only within the context of your own family. A red-haired man is shown enthusiastically giving a child a "milk mustache" -- drinking milk and showing off the white residue on his upper lip while shouting "Milk mustache time! Woo boo boo boo boo!" A woman standing nearby looks on with visible disapproval.
The caption below reads: "Lesson learned: Some things are only appropriate with your own children." The implication is that this man is not the child's father, and what would be a charming, goofy dad moment with your own kid becomes deeply creepy and inappropriate when done with someone else's child.
In the votey panel, a woman tells the man "That's not socially appropriate," and he sheepishly replies "Terribly sorry, ma'am," confirming that he was indeed a stranger performing this bit with a child he did not know. The humor comes from the absurd gap between the innocent silliness of milk mustache antics and the social horror of a random adult doing this to an unfamiliar child.