# Is penis in vagina sex instinctive?

**URL:** <https://boards.straightdope.com/t/is-penis-in-vagina-sex-instinctive/641491>\
**Category:** Factual Questions\
**Created:** [November 19, 2012, 10:51am UTC](https://boards.straightdope.com/t/is-penis-in-vagina-sex-instinctive/641491 "2012-11-19T10:51:46Z")\
**Posts on this page:** 4\
**Page:** 4

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**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\
**Post date:** [November 28, 2012, 1:27pm UTC](https://boards.straightdope.com/t/is-penis-in-vagina-sex-instinctive/641491/61 "2012-11-28T13:27:42Z")

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> [@foopyx](#):
>
> I’ve unfortunately seen a video of a woman’s index finger being placed rather vigorously into a man’s urethra.
> 
> I understand that it sounds ludicrous, but I assure you it exists. I bet google could confirm it.
> 
> ETA: it was a sex act, and the man appeared to enjoy it a great deal.

While \*your \*penis may be the same size as an index finger, most men’s penises are quite a bit larger.

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**Author:** ![foopyx](https://avatars.discourse-cdn.com/v4/letter/f/3e96dc/32.png) [@foopyx](https://boards.straightdope.com/u/foopyx)\
**Post date:** [November 28, 2012, 2:31pm UTC](https://boards.straightdope.com/t/is-penis-in-vagina-sex-instinctive/641491/62 "2012-11-28T14:31:49Z")

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> [@WhyNot](#):
>
> While \*your \*penis may be the same size as an index finger, most men’s penises are quite a bit larger.

I get the feeling you read what I wrote too quickly.

Allow me to reiterate: a female digit was inserted into man’s urethra. Vigorously. Repeatedly.

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**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\
**Post date:** [November 28, 2012, 3:39pm UTC](https://boards.straightdope.com/t/is-penis-in-vagina-sex-instinctive/641491/63 "2012-11-28T15:39:56Z")

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> [@benbo1](#):
>
> A documentary on tv a few years ago (I believe with Desmond Morris) speculated that missionary position became the most instinctive after we became erect. I mean, when we started walking erect. The reasoning is, the female breasts, which were previously considered ‘unimportant except for feeding’ (!!!), didn’t look anything like the rounded globes that they do today (all individuals are different, your mileage may vary, etc.). Now here’s the kicker - the breasts came to resemble, in the anthropologists opinion, the other roundly-shaped thing on a woman that drives men crazy with lust. In other words, we started going missionary because the boobies started looking like the ass!..

This theory is not accepted by all anthropologists and sex researchers, IIRC.

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [November 29, 2012, 1:45am UTC](https://boards.straightdope.com/t/is-penis-in-vagina-sex-instinctive/641491/64 "2012-11-29T01:45:38Z")

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> [@](#):
>
> Allow me to reiterate: a female digit was inserted into man’s urethra. Vigorously. Repeatedly.

Yes, and the insertion of a finger into a urethra does not imply that a penis can fit into a urethra, because a penis is larger than a finger.

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