Much later, I deduced that it was a euphemism for "full of shit", though I think the tone was milder than it would be for the original phrase.
There was also mention of an "effing knife" in a Max Shulman novel (a satirist from generations ago, pretty much forgotten, I think). I thought it was some technical sort of a knife, but eventually, it occurred me that it was another euphemism.
The modern taste for actually using curse words has removed a cause for minor ingenuity.
This entry was posted at http://nancylebov.dreamwidth.org/478932.html. Comments are welcome here or there. comments so far on that entry.