Are the multiple penetrations that occur in sex biological or cultural?

Please try masturbation, Mr. / Mrs. Umbridge.

Umbridge, have you checked out any references online for information about sex? The Wikipedia article is a pretty good primer.

And have you looked at any videos? If not, why not?

I don’t need you to share the whole story of your parents here, but I do hope you realize that the story you gave above is mainly the story of when your parents didn’t have a relationship, and it ends with your birth, meaning you’ve omitted 96% of their relationship. (Since 24 out of 25 years were not discussed.)

There’s also a lot of “probably” in there, and any one of those would be an excellent way to start a conversation. So, dad, why didn’t you date anyone until you met mom? How did you figure out what to do in bed? (or maybe phrase it as “How will I figure out what to do in bed when I marry?”) Did you and mom plan to get pregnant right away? How come I don’t have any siblings? How did you keep your relationship successful for so many years?

Some families/cultures have no problem being very frank about sex… but even if they stick to a PG version of the answer, those questions are all things that a parent should be prepared to answer and that you’d benefit from learning. Because, really, the kinds of things you’re wondering about are pretty similar to wondering if they’re actually reptiles.

I watched A Girl’s Guide to 21st Century Sex (British 2006 TV series). It is a documentary on Youtube. Because it is so long, I did not finish.

Have you watched any of the widely available videos on the internet that show adults having sex? If not, why not?

Sex is one of the greatest overrides to ‘normal’ behaviour. If you think about intercourse from a purely functional (I.e. procreative) stance, then lots of the things we do in bed will seem strange, icky, unhygienic and even dangerous. We employ our fingers, tongues and other appendages to stimulate parts that, under other circumstances, we find slightly shameful and suspect may be germ ridden. Nevertheless, when you engage in sexual activity, all that changes.

OK, I’m going to assume you have never orgasmed, if I’m wrong I mean no insult.
That being said, orgasm typically it requires a certain amount of manual stimulation, thus the repeated thrusts.
Why this level of manual stimulation is required I cannot say, perhaps one of our more educated dopers can address that issue.

Voyeurism.

Please do NOT avail yourself of porn in an attempt to learn about sex, Umbridge. It’ll just distort your thinking.

What does voyeurism have to do with watching videos of actors being filmed while having sex? How does this answer my question?

I strongly disagree, though I’ll admit there’s plenty of stuff out there that people might find weird. I think it’s normal, healthy, and can even be educational.

Please understand, Umbridge, that a vast majority of posters participating in the SDMB are Americans. Consequently, for many of us, our experiences with sex is that it is something that most late teens and adults do, and they do it mostly for pleasure. Either with one or more other people, or individually. Since in our experience, the mechanics are widely known at a fairly young age, when we encounter questions like the ones you are posing, it sounds so very alien to us.

We are left very curious as to how someone could reach adulthood without picking up the fundamental information about what sex is, how it is done, why people do it, the pleasure aspects, assumptions about our parents having (at one time) active sex lives, etc.

In addition, your questions have a very clinical / intellectualized / abstract tone. This is somewhat normal for a person with no firsthand experience, I suppose. But it still comes off as very alien. In our world, it is normal to be very curious about sex, which you seem to be, but there is an edge that suggests the curiosity is because you are writing a paper, rather than wanting to explore the subject as a participant.

Umbridge needs to find someone of his/her preferred gender and perform some experiments.

Being American has jack to do with it.

Most people of all cultures throughout history experience sex as teenagers or young adults. This includes all the likeliest candidate countries for Umbridge’s parents.

If a 24 year old human adult is this profoundly unfamiliar with sex, it’s not due to culture but an almost unbelievably sheltered upbringing. Even in India/Pakistan/China/etc, teens have sex. Or at the very least know about it and have ways of learning more.

And as mentioned a few times now, they almost certainly know and/or have seen animals also demonstrate rhythmic thrusting during copulation.

ETA: It’s based on self-reporting (therefore, somewhat unreliable) but the average age of first intercourse is less than 24 years old across the world. That means a majority have experienced and an even greater majority likely know a good number of these details. And this isn’t some new historical accident. People lived in closer quarters in the past. The idea sex was any kind of secret in the past is historically unsupported.

More multiple penetrations, maybe some candlelight and wine.

I was the first viewer of the OP earlier today, and I had a lengthy post written asking Umbridge to please come clean (heh, heh) about what’s up with all these sex posts (troll? odd sense of humor? Actual 12 year old?) but thought I would probably be accused of threadshitting, especially as the first response.

Andy, I love porn as much as the next middle aged, happily married guy, but I don’t think it’s good in the absence of a more normal guide. I mean, I’d love to have a sex life like that, but the reality is that most of the women I have been with are far less… adventuresome than those movies portray.

Porn is almost always for the dudes, and as a fantasy/masturbatory aid I think its fine. But I haven’t known too many women who actually like facials.

I’m talking more about the mechanics of sex and different positions, which is what the OP seems most interested in. I didn’t fully understand the anatomy of sex until I first saw a porn (a long, long time ago).

Ok, I can grasp the idea of a 24 year old guy still being a virgin. It’s unusual but it’s not something that I consider freakishly rare or anything. What I can’t grasp is the idea of a 24 year old guy-a guy who is obviously interested in sex, as evidenced just by his threads here-that has never even masturbated before.

If the OP had ever even masturbated before, he would already have the answer to his question posed in the OP. Why do you use multiple “hand jerks” when pleasing yourself? For the same reason “multiple penetrations” occur during PIV sex.

Consider me dubious.

Multiple Penetrations? You mean like DVDA:

http://www.urbandictionary.com/define.php?term=DVDA