I would have thought it was the obvious time. Midwinter: priests are haranguing people: you’re cold and tired: there’s a party: there’s free alcohol provided by someone else: and of course it’s when Jesus Christ was born. So there. Go to it teenagers.
In 1966, at Christmas, I first cuddled my first proper girlfriend properly, in a big armchair, in a darkened room, while the softer slower record was put on at the party, by the parents of the host, in the other room. I was 14, she was 13. My friends in the same room were the same age or not much older. We were all in the “Lower Sixth”.
Now THAT was what we called “sex”! (But it was before sex was invented on the Wireless Tele Vision.)
I still wonder about her even today.