Something you "get" when someone says or does something stupid. When someone does something stupid, someone can say, "let me get my dummies" and shove their head. However, when someone does skmething stupid, they can say "no dummies" and people cannot get their dummies. If someone calls dummies, they can also call "worldwide" where everyone can get their dummies on the person who did something stupid. As with "no dummies" the person who did something stupid can call "no worldwide" so only the first person to call dummies can "get their dummies."
George: Are humans the same thing as people?
Tom: Let me get my dummies, worldwide!
(everyone comes and pushes George in the head)
Sam wears jeans to baseball practice without knowing it. He realizes his mistake and says "no dummies"
Teacher: If x=1, what is the value of x?
John: the coefficient of y to the power of 6
Herbert: let me get my dummies!
John : No worldwide
(Herbert gets his dummies on John, but no one else can)