Okeydokey--now from a geezer babe--
As a child in the fifties and a teen in the sixties, I have old fart(ette) information.
Back in the day, oral sex was rarely talked about. For most of us, our first experience did come quickly, but after vaginal sex, and frankly, it often was a bit of a shock--"You want me to do WHAT? And you want to do WHAT to me? Are you kidding?" Of course, we tried it, we liked it and, for you young'uns who won't believe it--we're still doing it. Really.
But, back in the day, you only might mention it to your very, very closest girl friend. Or, you might not. It became a (rather delicious) secret.
It probably wasn't until the eighties that we realized that everyone was doing it and always had been. However, we did maintain the mindset that it was the frosting, and vaginal sex was the cake.
I'm not sure where anal sex fits into that analogy. Perhaps we ought not go there.
So that's the history of my generation. Maybe I'll ask my 92 year old mother about the WWII generation. I'm sure with less reliable birth control of that day and the fact that men and women have always been bonking, oral and anal sex were part of the repertoire even back then.