Julian Jaynes said that only after people became self-aware around that time -- exercising introspection -- did they become aware of their drives and urges, now viewing them as things that needed relief. If they weren't relieved, tension built up; hence the birth of anxieties about unmet urges. And once you think about how to relieve tension, our rational capacities generate a list of many solutions -- not just intercourse, but sodomy, oral sex, masturbation, getting jerked off, as well as those practices but with someone of the same sex.
These and other forms of deviance were condemned in the Old Testament, most notably in the stories about Sodom and Gomorrah in Genesis, written during the 6th century B.C. or shortly after. Yet in the Code of Hammurabi, written around 1780 B.C., proscriptions about sex only relate to rape, marriage, divorce, adultery, and slander -- weird things like sodomy, homosexuality, bestiality, etc. just did not occur to people back then.
Our best guess about what life was like far back into pre-history is what contemporary hunter-gatherers look like. They're not the exact same, but they are our best guess. Archaeology and history provide another guess, and I'll get to those in another post. This paper by Hewlett & Hewlett (2010) is the first to quantitatively study sexuality in "pre-state" (= primitive) societies, one a group of Pygmy hunter-gatherers (the Aka) and the other a group of slash-and-burn farmers (the Ngandu), both in central Africa. It also includes a review of other cross-cultural studies of sexuality.
It won't surprise readers here to learn that homosexuality is absent among both groups. However, you might not have suspected that masturbation is not only absent but unheard of.
Like homosexuality, it was difﬁcult to explain self-stimulation to the Aka. They found it unusual and said it may happen far away in Congo, but they did not know it. A speciﬁc word did not exist for it. We asked men, in particular, about masturbating before they were married or during the post-partum sex taboo and all indicated this did not occur.
So it's not just that men are married and getting frequent sex -- even before they enjoy regular conjugal benefits, they do not masturbate, or know what it is to begin with. And it's not limited to the people in this study alone:
We asked Robert Bailey (personal communication) about his experiences of trying collect semen for fertility studies from Lese men in the Ituri forest of the Democratic Republic of Congo. He indicated it was very difﬁcult to explain to men how to self-stimulate to obtain semen samples. He said that despite explicit and lengthy instructions three of four semen specimens came to him mixed with vaginal secretions.
They quote an earlier cross-cultural review by Ford & Beach (1951) of 190 societies of various types. The original:
Despite societal disapproval, there is evidence that adult males masturbate, at least occasionally, in a few societies other than our own, although this behavior is apparently rare. . . some women in a few societies other than our own occasionally masturbate, although the practice generally meets with social disapproval.
So that's why in Vacation, Cousin Eddie's son had to explain to Russ how to "bop your baloney." How to move during intercourse comes natural enough, but practices that were never a part of our evolutionary past need to be explained overtly (hopefully not demonstrated, in this case). They persist through cultural rather than genetic evolution.
Oral and anal sexual activies were unknown or very rare. Ngandu men who traveled to the capital city were familiar with oral sex and said they liked it, but said women in the village did not do it. One Aka woman said that a “man never puts the clitoris in his mouth; if he does he will vomit.”
And who said there's no such thing as the noble savage?
As for other societies, they don't mention oral sex in their cross-cultural review section. The first item I hit on from googling is the book Our Sexuality by Crooks & Baur, which mentions that outside of the modern world, only in the South Pacific islands do they practice oral sex; in sub-Saharan Africa it's unnatural or disgusting. There's no citation, but allowing it in for the sake of argument, primitive peoples still rarely or never practice oral sex. Here is an article mentioning that the Inuit (= Eskimos) don't practice oral sex either; they are historically hunter-gatherers.
That book also cites Ford & Beach (1951) to the effect that even kissing mouth-to-mouth is pretty rare -- only acknowledged in 21 of 190 societies (11%), and as something before or during intercourse in just 13 (7%). Kissing was therefore not part of our species' evolution. This explains why it's more common for a girl to be awkward/bad at kissing or giving oral than at actually getting it on. (I assume girls would say the same about us.)
Well, with so little awareness of kinky practices, they must be prudes who rarely get any action, or feel shy and ashamed when they do, don't reach orgasm, etc. In fact, the Pygmy hunter-gatherers have sex around 7 to 8 times a week on average, compared to 1 to 2 nights for contemporary Americans, with the Ngandu farmers being in between at 4 nights.
As for shame:
About half of the Aka men and all Aka women said either the man or woman can initiate sex, while among the Ngandu about half the men and women said either can initiate sex. Most Ngandu women said they were shy about initiating sex and complained about their husband’s advances. Aka women were not shy about initiating sex and did not complain about their husband’s advances.
I wonder if the Ngandu women are as shy/awkward as modern women are about initiating sex within a relationship, where generally the man takes the lead. Or if they complain as much as modern women do about their husbands asking for sex. Slash-and-burn farming is a good step away from hunting and gathering, though not as far away as settled large-scale agriculture and industry.
We did not investigate how often men or women had orgasm during coitus. Ngandu and Aka had terms for male ejaculation, but not for female orgasm. All informants clearly understood female orgasm as they described women shaking and trembling during coitus. Aka and Ngandu men indicated they climaxed each time they had intercourse during the night, while women generally reported experiencing orgasm, but not necessarily each time.
These two sets of findings are a real wake-up call to modern people -- a lack of hang-ups about sex comes bundled with a lack of awareness of, interest in, or practice of non-reproductive sexuality, i.e. recreational sex or sex primarily for pleasure. Oral, anal, masturbation, and homos are all clear signs of a frustrated society, unable or unwilling or whatever to met their basic needs in a natural way and using their rational and rationalizing skills to met them in more unwholesome ways.
That comes through in the reasons that primitive peoples give for having sex. As the article mentions about the two focus groups, as well as others in the cross-cultural survey, their main concern is with making new children, not private or mutual pleasure. Although they do get some enjoyment out of it, they also stress that it can be hard work sometimes.
So, the sex lives of primitive or pre-conscious or "bicameral" people are, to put it bluntly, more like those of animals. Even your house cat, let alone a wild beast, doesn't masturbate, doesn't give or receive oral, or anal, doesn't act queer, doesn't get neurotic over his unmet sexual urges, has sex for procreative purposes only, and although they may do it frequently, it's less of an attempted endurance run and more a series of "wham, bam, thank you ma'am."
Dogs are more domesticated and likely screwed up in similar ways that modern human beings are. They do hump your leg, the furniture, etc. -- the doggie version of doing a blow-up doll. Dogs also whine a lot more than other animals, wild or tame, and make those pathetic, "look how pained I am" kind of eyes, that they might be capable of anxiety or neurosis like we are.
Religions are often assumed, both by their adherents and their enemies, to be attempts to lift man up above his base animal nature. But the more you look at them, the more they look like cultural gadgets that we've invented to try to restore us to our more natural state -- hence all of that stuff about mankind before The Fall -- and away from the degradation, corruption, and perversion of civilized progress. The emphasis on sex as a primarily (though not exclusively) procreative act is just one case. That behavior is more animalistic than going down on someone or whacking off, which your cat would regard as proof #47 of why you're an inferior species.
It's the civilizing, liberalizing, progressive track that leads us toward becoming more humanoid than human. Suddenly the encouragement to try anything leads us into studying and memorizing some nerdy manual on kink techniques like the Kama Sutra, preoccupying ourselves with whether we're executing the instructions properly during the act, and worrying afterward about whether our customer ratings will be high or low.
Those things cause us to become self-conscious because our evolutionary history did not mean for us to go there, so we'll have to figure it out and monitor its progress consciously, when sex should be a case of "Let your mind go and your body will follow."