Common name for our American allies, derivation unclear but none the less very fitting.
Septic tank = yank
Petrol as in petrol tank = yank
North American so called allies that got us into a fix in Iraq due to our spineless leader lacking the backbone to say no, ram it Georgie.
Have a habit of downing allied aircraft and shooting up allied troops no matter what recognition method used although to be fair they do tend to shoot at their own troops/vehicles/aircraft with equal enthusiasm. This has been going on since at least 1944 when General George Patton threatened to take the 3rd Army out of the line, turn it 180 degrees and blow up the 8th Army Air Force airfields to stop the frequently incompetent blue on blue incidents the Army Air Corps were then inflicting daily on their own side.
In the same year, the USAAF managed to kill the US Army Chief of Ground Forces when one of their "Carpet Bombing" attacks in Normandy fell somewhat wide of the mark and landed in their own rear areas, killing General Leslie McNair and a rather large number of his compatriots.