%% Examples were removed for violating the content policy. DO NOT attempt to add new ones.
->''"Thank god for virgin 13-year old females writing gay porn."''
-->-- '''America''', ''Manga/AxisPowersHetalia'', "Buttsex: The Musical"

You would expect the people creating erotica to know how sex works, and yet, the movies often depict things that wouldn't really be enjoyable, should be done differently or are just plain weird. This is usually done on purpose, to conform to what the audience wants to be true. Some of these are perfectly AcceptableBreaksFromReality, since such works caters to [[{{Fetish}} customers' sexual fantasies rather than reality]] and is intended to provide an [[MaleGaze arousing]] [[FemaleGaze display]] of the participants rather than a strictly accurate depiction of the act.

In other words, RealityIsUnrealistic.

However, this also shows up in a lot of FanFic because said fiction tends to be written by teenagers who don't know all that much about sex. It can also be an effect of lack of research before writing about [[MostWritersAreMale anatomy that]] [[MostFanficWritersAreGirls the author lacks]]. Better to just use a SexyDiscretionShot and call it a day.

Sadly, this trope sometimes pops up in works and speeches not clearly labelled as fiction: In RealLife, sex education [[RussianReversal fails YOU]]. The average high school sex ed course in many countries, especially the United States, is often so hilariously incomplete and inaccurate that it leaves you completely unsurprised that most students walk away knowing very little.

Compare with IdealizedSex, where the sex is realistic in action but still more idealized than most sex in the real world. See MissConception, TechnicalVirgin, and ButWeUsedACondom for when characters are mis- or uninformed about sex facts.

!!Typical subtropes:

* BiggerIsBetterInBed (when sizes cross the fine line between "Wow!" and "I'm scared!")
* STDImmunity (well, biologically implausibly safe sex)
* RightThroughHisPants
* MisterSeahorse (men getting pregnant)

!!Common versions (no specific examples needed):
The common versions can be divided into three broad categories: exaggerations of reality, convenience tools, and completely impossible.

These remove inconvenient bits of reality. Certain needs that actual sex would require, but would affect the pacing of the sex/story.

* Implausible lubrication or complete lack thereof. Saliva and plain water tend to dry too quickly. Oils can degrade latex. Other works use things that are sticky or tacky.

These are at least theoretically possible, but for them to happen in reality would require nigh-superhuman sexual capabilities and/or stamina. Also covers cases where they are very possible, but the frequency of their occurrence in the wild is exaggerated.

* Doing it twice (in five minutes): Men tend to need a cool down period.
* Excessive amounts of bodily fluid.
* A virgin always bleeds: A very common and very old myth in real life, and thus it's no surprise that it turns up in many works of fiction as well. This perception is so prevalent that [[ConsummationCounterfeit faking it]] is a trope in its own right.
* All women are born with hymens, and a virgin always still has her hymen.
* Inversely, a lot of pieces focusing on TheirFirstTime or virginity as a fetish will neglect to mention ''any'' difficulties with the breaking of the hymen or bleeding or pain at all, or the woman in question is having so much fun she just gets over it without even taking a breather. Realistically, pain in such a tender spot can be a real show-stopper.
* Female orgasm from penetration alone.
* [[{{Anorgasmia}} The Elusive Orgasm]]: Since the 1990's, it's become a fairly common sex joke in comedies (film, television, whatever the case may be) that a male partner in sex has extreme difficulty giving his female partner an orgasm.
* All gay sex is anal.
* Sperm as guided missiles: Typically in fiction, if a couple have unprotected sex, the woman is absolutely ''guaranteed'' to become pregnant. It doesn't work like this in real life, as anyone who knows people ''trying'' for a baby can probably guess. [[LawOfInverseFertility This is only if the pregnancy can be used for drama, though]]. Otherwise, you can and probably will have a million Film/JamesBond-type characters who go around having rampant sex with the GirlOfTheWeek and never have to face a consequence.
* Nothing smells, tastes bad, or is uncomfortable: Anything that would in RealLife is glossed over.
* Everyone enjoys the same things: It's as true with sex as it is when it comes to pizza toppings.

!!!Plain impossible
These are not physically or anatomically possible by any stretch. They represent imaginative fetishes at best, or just severe cases of not knowing how human bodies work at the worst.

* Weird anatomy: Occasionally seen in hentai, and really common in fanfics written by virgins. This generally involves misplacing body parts or making them connect, stretch, or move in ways impossible in real life. Sometimes done on purpose in SciFi and {{Fantasy}} but otherwise generally a sign of either ArtisticLicense or lack of research.
* Mistaken terminology: Many writers don't actually know what names correspond to which body parts. This can lead to weird anatomy as mentioned above. Most of it is a result of badly done sex education classes which result in writers not knowing the proper terms or assuming that everything down there is the same thing.
* Bizarre comparisons: A staple of PurpleProse, this most likely is done for either romantic or erotic reasons.
* Implausible positions: Many of these would dislocate some joints if performed in real life.
* "Go fuck yourself!": The euphemism [[ScrewYourself turned literal]].