Its an American thing; To some people around the world, we do have strange ways to get our message across.
Rustle. to find, to get, find or steal.
Grub: Food in this this case, not a small pre-pupae insect
It is like the first time I came across the term Vegimite. Australians and Kiwis also have their colourful way of getting their message across as well.
If their was to be a contest as to who can say the darnest things, I still think We Yanks have everyone else beat.