To tumble-weed is to add a comment to a joke, or add comment to a conversation that kills the flow and creates an awkward feeling among the group for a short amount of time. Then the group proceeds to say "Tumble-Weed!" and is they happen to have long curly ginger hair they shake their head about.
person 1 = "Yeah shes my bit on the side"
person 2 = "im yours too!"
person 1 = "Ha Ha i have too bits on the side!"
Tumble weeder = "you could say you have a piece on the side!"
Everyone = "TUMBLE-WEED FARROW!"