History Main / NaughtyByNight

* ''Film/MySuperExGirlfriend'': Vaughn thinks Jenny is this on first seeing her, saying though she looks like a librarian on the outside, inside there's a wild side. He's more right than he knows. As her alter ego G-Girl, she's revealed to be a very enthusiastic lover she accidentally injures Matt with her super strength.

* Erika Kohut in ''Literature/ThePianoTeacher'' by Creator/ElfriedeJelinek is a very unhappy example. Her [[MyBelovedSmother oppressive mother]] has totally managed to suppress her natural sexuality, so she tries to make up for it by secretly and obsessively pursuing weird, unhealthy perversions, though she can still barely feel anything. When she gets into an affair with her student, he soon gets freaked out.

* The title character of the 1984 {{Sexploitation}} film ''Angel'' and its sequels. The tagline for the original movie was "High School Honor Student By Day. Hollywood Hooker By Night".

* The Music/GoodCharlotte song ''Like it's her Birthday'' has this as the main theme -- the Protagonist thinks his Girlfriend's [[YourCheatingHeart cheating on him]] when she lies about where she's going, so he follows her and...

[[YourCheatingHeart Now I'm not saying that she's cheating, but seeing is believing]].\\

* The [[HeroesWantRedHeads red-headed librarian]] from ''Film/{{Tomcats}}'' looks like a plain, uptight young lady. She (and her grandma!) are also into S&M.

** Ditto for the manga/anime ''Sprite: Between Two Worlds'',wherein Manami, a severely repressed and meek college student turns into Nami, an outrageously uninhibited flirt whenever she's put into any situation that is too much for her to handle. The catalyst is her cousin Toru, who convinced Manami to be more confident around him when they were young by convincing her she was really Nami.

* A relatively tame version occurs in ''Literature/GoodOmens''. Sweet little old lady and part-time medium Madame Tracy also offers appointments for "strict discipline and intimate massage every evening except Thursdays", and there are hints that she goes a little further than that on Thurdays.

* ''VideoGame/LeisureSuitLarry 7'' got this one, cranked up to 20, with HotLibrarian [[PunnyName Victorian Principles]].

* Somewhat subverted in the film ''Film/BlindDate'' where Creator/BruceWillis' sister-in-law tells him not to let the date get drunk as she goes wild. This information is relayed to him via his brother who adds lots of leering to the information. Cue the man getting his date (Kim Basinger) drunk, to find that she goes wild in a drunk-driving, crash-the-car, ruin-the-evening way.

* Sheila from the US version of ''Series/{{Shameless}}''. By day she's a sweet agoraphobic and germaphobic housewife. But at night she is very very into pegging filthy alcoholic Frank.

-->''You make me so happy
But there's all these people around
So wait til I get you home

* the Music/GoodCharlotte song ''Like it's her Birthday'' has this as the main theme -- the Protagonist thinks his Girlfriend's [[YourCheatingHeart cheating on him]] when she lies about where she's going, so he follows her and...

* Subverted on ''Series/PersonOfInterest'' where a [=PoI=] is a dedicated workaholic doctor during the night but seems to spend her nights going to night clubs and picking up men. However, a more detailed investigation reveals that she is actually [[spoiler: stalking the man who raped her sister and caused the sister to commit suicide. The doctor is simply building up her resolve to murder the man.]]

Compare SeeminglyWholesomeFiftiesGirl and CovertPervert.

Alice is a [[HotLibrarian librarian]]. During the day, she wears long skirts, a loose blouse done all the way up to her neck, her hair in a bun and sensible shoes.

* In the manga ''Manga/CrimsonSpell'' the protagonist is under a strange curse that causes him to turn into a [[HornyDevil Demon]] that can only be vanquished by being ''raped'' into submission. Conveniently he never has any memory of this the next day.

Compare SeeminglyWholesomeFiftiesGirl.

[[folder:Live Action TV]]

* the Music/GoodCharlotte song ''Like it's her Birthday'' has this as the main theme -- the Protagonist thinks his Girlfriend's cheating on him when she lies about where she's going, so he follows her and...
-->''"Tonight I kinda get the feeling/My girl is up to something, Something that is no good/ She said she only had a meeting/ But she is dressed for something, Something that is no good/ [[YourCheatingHeart Now I'm not saying that she's cheating,]] But seeing is believing/ [[InVinoVeritas Can't believe it, What I'm seeing when I stepped inside.]]"''

* In ''{{WesternAnimation/Futurama}}'', a prim bureaucrat is utterly turned on after hours by Fry's horrifyingly slobby lifestyle.

Sarah is a [[HotLibrarian librarian]]. During the day, she wears long skirts, a loose blouse done all the way up to her neck, her hair in a bun and sensible shoes.

Get Sarah home to her significant other, however, and well -- the [[DressHitsFloor blouse is going to be on the floor]], the skirt in the hall, her [[LettingHerHairDown hair all over the place]]... and the rest is too {{NSFW}} even to describe. As strait-laced as Sarah may be in public, none of that carries over into her private life -- and vice versa.

[[folder:Anime and Manga]]

* Almost every Cairheinan noblewoman in the ''Literature/WheelOfTime'' is heavily implied to fit this trope. Though during some festivals they will run around almost nude on the streets, especially during the Feast of Light (during which normal prohibitions against inter-class kissing (and other things) are lifted), leading to a large number of commoners having bragging contests about who made out with the most important noblewoman.