Yellow Diamond is one of the leaders of the Diamond Authority in Steven Universe, the Cartoon Network animated series about the Crystal Gems, and she is known for her strict, impatient and commanding presence. Her line shut your mouth fits that personality perfectly, which is why fans lifted it from the show and shared it as a short reaction sound. On soundboards and in fan edits it is used to end arguments, mock long-winded explanations and play up her authority, and its brief length makes it easy to drop into videos, memes and chats without losing the joke.