In the nonsensical court case between the lords of Baisecul (Kissarse) and Humevesne (Sniff-fart) in Rabelais’s Pantagruel, Humevesne observes that among all good bagpipes, when hunting for birds and swinging a broom around the chimney three times, one only blows into the arse (‘souffler au cul’), but as soon as we see the letters, the cows will be returned to him.
Blowing into the arse is of course a waste of time for there is no point breathing into something that is perfectly capable of producing its own wind power. It’s so much hot air, like the court case, which drones on like the bagpipes Humevesne mentions, full of wind but empty of substance.
Dominic Hills’s animated illustration of this expression gives it an industrial feel, like a poster from the Soviet Union, exhorting us to Stakhanovist levels of bottom blowing: