Interchangeable with Yank or Yankee, a euphemistic stereotype for Americans who spill forth verbal filth like a sewage plant.
Mate, I took that septic tank from the other day out for a surf. I was hoping the sharks would rip him to pieces but it looked as though they swam away in terror. It seems not even a Great White Pointer can swallow his bullshit.
Ordinarily used by Yankees as an offensive term for Canadians, especially in reference to sports teams as make beliefs sounds a lot like the Maple Leafs of Toronto (a Canadian ice hockey club) and the Maple Leaf is the national symbol of Canada.
Yankee: The Make Beliefs shouldn't even be a part ofthe NHL. They're not even American.
Canadian: Quit trying to Yank my chain. You Septic Tanks just can't accept your repeated failed attempts at Global dominance.