It was from the episode where’s there’s a heat wave and the Simpsons buy a pool. Bart and Lisa hear the jingle of an ice cream truck which passes them by saying that they’re all out of ice cream. Bart and Lisa hear the jingle of what they thought was another ice cream truck but it was selling hot chili instead.

I didn’t understand that one either and was wondering the same.

They have boiling hot, Texas style ginger ale.