I still think the modern interpretation works better for the scene. She’s clearly telling her mother the most ridiculous thing she can think of, to chide her for being nosy. And so the more ridiculous the thing she says, the better it works.
It’s not ridiculous for George to be sweet-talking her, nor for her to tell her mother that he is. It is ridiculous for him to be boinking her right in their entrance foyer as soon as he arrives, and even more so for her to be saying so.
So…Big Bang was riffing off of IAWL. Who knew?
After Mary ran to hide in the hydrangea bush, losing her robe en route:
George: “This is a very interesting situation. A man doesn’t find himself in a situation like this every day. Not in Bedford Falls, anyway…”
But notably, when they hear a car driving up, George quickly hands Mary her robe.
IMO no movie hits on more emotional cylinders.
Just this evening I read this passage in David Copperfield:
It seems but yesterday to me, John, when you were a little creature, a head shorter than Master Copperfield, making baby love to Annie behind the gooseberry bushes in the back-garden.
Poking around, I found that the New International Version of the Bible, published in 1973, uses “made love” in Genesis as the euphemism for sex, replacing “knew” from earlier versions.
As I understand it, the NIV was widely read and influential. I wouldn’t be surprised if it transformed “making love” from verbal to physical in the common language, either as a new phrase or a popularization of something already changing in the language.
It definitely didn’t originate it, as the NIV specifically looks to established English usage to decide how to translate. That’s why the 2011 edition now finally uses singular they for unspecified or unclear gender, instead of the older “he” or the less old recasting the sentence to use the plural.