to what I read. Or, failing that, to how I repeat it. I happened to notice a large sticker pasted over the back of someones truck. 'Sucking gas, hauling ass'.
That's what I saw. What I said, when repeating it, amused, was 'Sucking ass, hauling grass'.
Fortunately the owner of said truck took the spoonerism in his stride; I fear I have achieved a dubious celebrity.