This Snopes article has some relevance to this discussion:
Here is an illustrated Wikipedia entry on a variety of sex posistions (NSFW photos, broken link, remove spaces after //)
http:// Sex position - Wikipedia
“Doggy style” (woman on all fours, man behind) is spectacular, and most of my past female partners would agree. I’ve never had a “slipping out” issue with it. That does happen in the laying down “spooning” doggy style position sometimes though.
<Images of a new Geico porn ad fill my mind, and even the gecko gets involved, if you remember how they use hamsters> Thanks, marshmallow.
Yeah, sorry about the stupid question. I thought “doggy style” meant anal sex. Still sounds uncomfortable to me, but of course I wouldn’t know.
(maybe someday there’ll be a “ask the asexual” thread)
I don’t remember. How do geckos use hamsters?
You’re not alone! My wife and I also knew that Plug A goes into Socket B, but getting the angle right is exactly what my problem was. It took many months of trying, but we finally got it right.
To answer your other questions, my guess is that it is partially instinctive. Thus, many/most people figure it out with less or more difficulty, and some with extreme difficulty. Perhaps the same is true with animals, and the ones who never figure it out never have offspring. But the species doesn’t die out, because of the great majority who do figure it out eventually.
It doesn’t have to be an all-or-nothing deal; it’s a sliding scale.
The reality is that information is perhaps the most important thing that parents pass on to children, and that is not just a human thing. Cats may have an instinct to hunt, but they’ll starve without a parent to teach it. Elephants pass down memories of oases and food sources without which they’d all starve. Birds have to push the chicks out of the nest to get them flying; many would never learn that on their own. Language has to be taught in humans as well as in other animals.
So if a young animal cannot even feed itself without parental instruction, why shouldn’t parental instruction be crucial in learning to reproduce as well?
It’s us humans with our technology, wealth and Victorian mores who think its normal for virgins to mate with each other and who think it’s improper to have sex in front of other members of the tribe/pack/whatever. We needed this much intelligent just to figure out how to complicate it.
Heh. Rigor.
Lady Dopers are welcome to come and fight mine. 
Yes, I believe this to be so. But it’s not so clear that you can separate sex/courtship from the overall inability to engage in social activity.
As for the OP, I don’t believe there is any evidence that we have an instinct to have sex, although we certain have an instinct to get aroused and we quickly learn what to do to make that arousal more, how shall we put it… intense?
Keep in mind that a human reared without social contact with other humans is so stunted emotionally and intellectually that said person wouldn’t be recognizably human. But any normal person living in a social community would have the ability to observe sexual acts in humans or animals.
Even in the “puritan” days, there was plenty of sex, marital and extra-marital. And you have to think that most people couldn’t be that ignorant, since houses were so small and many families lived in one- or two-room cabins. Mom and Dad probably tried to be pretty discreet, but how could the kids not have realized what was going on, and probably asked about it at a young age? (As a kid who lived in horror of hearing my parents, I’m glad I grew up in the 20th century!!)
Put a boy and a girl on and island with nobody to teach them anything, and eventually horny will kick in. They may not be able to express it or understand it, but they will both find they have an itch that needs scratching, and they both will inexplicably want to be close to the other, and will want to be touching each other when that itch strikes. They will figure out that the other one really likes it when they touch them between the legs like they like touching themselves, and will then figure out that its even better when the two bits are rubbing together. Eventually during all this rubbing tab A will slip into slot B on accident(or maybe they are clever and one will realize that one of them has a tab, and the other a slot… we are natural tool users after all, if you’ll pardon a little pun), and they’ll figure out that this is what they were supposed to be doing all along.
Just because they have nobody to teach them doesn’t mean they aren’t still human, and don’t have the associated gigantic brain that is hell bent on figuring things out. Sex may not be explicitly explained by instinct, but horny sure is.
And, of course, all it takes is 1 pair to figure it out. Once they do, any others will notice immediately and think, holy crap! We need to try that!
Hell… I had never once seen porn or heard about jerking off when I first started. I just know my little friend downstairs that I peed out of was inexplicably hard as a rock, and started rubbing it, which felt really, really good, so I continued. Technique was sloppy at first, but like our island dwelling friends, I have a large brain and figured out what worked and what didn’t.
My position (heh) is much the same as others have said about most animal young needing training, but I’d argue that it’s so much more true of us humans. As much as any other primate, we’re social, and we would go truly nuts if we had no supply for that need. We’re tool-users, and we’d quickly starve or get eaten if we didn’t have someone to show us how to use tools. That is, our basic survival truly depends on our learning from others. And we’re very good at it, better at it than any other species. It works for us.
That, and the other point that I’ve seen partly addressed: I of course haven’t personally experienced what female arousal is like, but it gets moist down there. I’m not sure how much of this would be instinct, but it seems to me that either the horny male or the horn-loving female would figure that of all places to put the horn, that lubricated place would be ideal. The rest would be instinct, I think. But that’s when we kind of stop thinking, isn’t it? Or just males?
I’ve seen an awful lot of nature documentary footage, not to mention reading about attempted dog breedings, that would suggest that not all animals have it down pat from the start. Anyone who has ever seen a dog trying to hump the head of another dog (or your leg or your bedroom slipper) should realize this.
Sex is, at least among some mammals, to some extent a learned activity. That learning can take place by transfer of knowledge from example or teaching OR it can take place via experimentation. Bonobos take it to new extremes, having vaguely sexual activities among just about any combination of sex and age you can imagine, kind of like a cross between a handshake and a verbal welcome or pat on the back - symbolic, but usually not reproductive. I doubt that’s entirely hardwired; I suspect it’s a learned cultural thing. It works for them.
I suspect that learning by experimentation between a couple with no experience, no preconceptions, and no inhibitions would be a lovely way to learn. They might not end up conventionally, but they’d probably end up pleasing one another very well eventually.
How did Chris Atkins and Brook Shileds learn how to do the nasty, in “Blue Lagoon”?
As I recall, they seemed to do OK.
That was fiction, ralph.
@ njtt’s comment “The most likely explanation, to my mind, is that humans, unlike other animals, wear clothes, and thus do not normally get to see what members of the opposite sex have down there”
I think humans have spent far more of their existence not wearing clothes, than they have wearing them.
That’s to misrepresent their views. Sex was viewed as a gift from God, and, as such, intended to be enjoyed - but only within the proper context of marriage.
Man gets aroused: his penis shaft gets hard.
Woman gets aroused: a hole in her becomes lubricated.
Seems pretty obvious to me.
It is not necessarily obvious to a woman that she “becomes lubricated.” It is certainly not obvious to a man that a woman has done so.