When you got the cheese and use it to make sandwhiches in The Legend Of Zelda.
The original creator of the legacy can be found here on Wagintrowl youtube channel
The phrase is used to mean “How is this relevant to the conversation?”, especially if a person seems to be actively avoiding the topic being discussed.
Me: Hey, do you have that $20 bucks you owe me.
Him: Hey, have you seen the movie Hot Tub Time Machine yet?.
Me: What's that got to do with the price of cheese in China?