I learned some new Aussie slang today. Their down-to-earth slang is almost identical to Irish slang, which is why I feel so at home with it.

An Aussie podcaster used the expression today. He used it while referring to people who believed something that had no basis in reality -- Americans would say, "You must be smoking crack, bro!"

But this guy said "They must be sucking on the end of a glass barbie."
It took me a minute to figure out what the heck he said. Then I figured it out.
First of all, "barbie" is barbecue [grill] in Australian slang.
A crack pipe looks a bit like a barbecue or chiminea; it gives off smoke at the top. And they are always made of glass.