Your Blank Is Showing

Two or more people are talking, and one says to another "hey, your (blank) is showing." Its usually a word that rhymes with penis or sounds like it could be a taboo word. It causes the other person to say "where?!?"

A variant that used to be common was "Your slip is showing" (the female undergarment type of slip).

Film - Live Action

 * Variation in The Naked Gun. Anna Nicole Smith's character says it to Drebin during a chess game. "Your bishop is exposed".

Music

 * Explored in the song "Underwear" by Royal Republic.

Western Animation
"Buttercup: Careful, Bubbles, your ego is showing! Bubbles: What? Where? Blossom: Come on, let's get going!"
 * In The Simpsons episode "Bart of Darkness", Nelson taunts Bart by saying "Your epidermis is showing!". This causes Bart to lose his balance, fall off the diving platform and break his leg. (As an added joke, Nelson thinks epidermis means hair.)
 * From an episode of The Powerpuff Girls:

"Spongebob: Patrick, your genius is showing! Patrick: *covers his crotch* WHERE?!?"
 * From the SpongeBob SquarePants episode "Texas":


 * In "Sahara Hare" Bugs Bunny tells Yosemite Sam (who is dressed in the flowing robes of desert folk) "Your slip is showing."