Somewhere I read an interesting article about how the Judeo/Christian religion transformed the idea of sex into being a mutual relationship between a man and a woman.
The article spent a lot of time saying how the pagans, Romans, etc. viewed sex only as the one penetrating and the one receiving. So gay sex, sex with objects (”Some guys - only having “sex” with a shoe will satisfy them”), meaningless sex, it was all fine.
Similar to “armpit sex” I suppose.