Backpedaling on the Relationship Upgrade (or at least trying to). A pair that's had their first kiss, or made out, or even gone straight from zero to sex in 30 seconds, will mutually decide afterward to pretend nothing happened. Cue cries of outrage from the Shipping crowd.
If the two were Kissing Under the Influence, if Aliens Made Them Do It, if there was a Love Potion involved, or if it was some other form of Deus Sex Machina, it's almost believable when they successfully do just that. After all, the feelings weren't real (or they can at least pretend that's the case). They may not even be in a Romance Arc at all; just two characters randomly selected to supply the sex appeal for the episode (though now that they've had romantic contact, they're guaranteed their own shippers anyway).
If there was no excuse other than raw passion, however, there had better be some sort of change in their interactions or the believability breaks down. You can't hold on to the old relationship status quo after you've voluntarily swapped fluids. After all, Sex Equals Love.
The phrase may be used explicitly, or the decision may be implicit, with the two pointedly talking about everything but what just happened.
Not the same thing as Fanon Discontinuity, which is when the fans are the ones pretending something didn't happen, or one way of saying You Didn't See That or Let Us Never Speak of This Again after mild non-relationship embarassment. For another form of backpedaling, see Relationship Reset Button.
- In Axis Powers Hetalia, Japan, after getting a lesson in sex (and being very loud during it, to say the least) from his close friend Greece, furiously tries to write it off as "just a dream" the morning after. Apparently he was too panicked to realize that calling it All Just a Dream just opens the door to a whole host of other implications...
- An interesting variation occurs in the Boys' Love manga Challengers. When Morinaga finally tells his sempai Souichi that he loves him, as an explanation for his desire to quit university to get away from him, Souichi makes a pact with him that they will continue working together as lab partners and friends, and forget that he ever confessed. Since Morinaga was planning to sever ties with Souichi after confessing, Souichi's That Didn't Happen actually prevents their relationship from being aborted for good.
- Not quite the same thing, but in the Spin-Off sequel The Tyrant Falls in Love, one of Morinaga's major frustrations is that Souichi seems dead-set on keeping their relationship at a standstill by pretending after any revealing incident that they're still nothing more than friends. Even after having sex, saying out loud that he can have sex with Morinaga alone, kissing Morinaga of his own volition, and moving in together, Souichi appears determined to willfully block from his mind any implications that his homophobia may be misplaced.
- Played with in The Girl Who Leapt Through Time. Makoto performs several time leaps to make sure that Chiaki asking her out literally does not happen. Nevertheless, her relationship with him is still affected to the point that she might as well not have bothered.
- One-sided version where it's only a confession that happens, in Hayate the Combat Butler, after spending an enjoyable not-a-date with Hayate, Hinagiku confesses that she's in love with him, just as a train goes by not allowing him to hear it. His response is equivalent to "What did you just say?" her response is clearly this trope.
- Highschool of the Dead: Most of what happened in the "Drifters of the Dead" OVA didn't happen since they'd all been hallucinating from breathing the smoke from hydrangea leaves. The same couldn't be said for Rei and Saeko, who wound up up frenching each other, in the nude - while thinking they were making out with Takashi. After the effects had worn off and they realized what they'd done, they both agreed that what happened on the island, STAYS on the island.
- Sango of InuYasha takes this a step further; after declaring that she would rather stay and die with Miroku than save herself, when it turns out that Miroku is not about to die after all, Sango's response to his gentle teasing about it is to go into complete denial: "Did I say something? What did I say?"
- Mahou Sensei Negima! with probably too many to list. The most obvious ones are Asuna's Forceful Kiss with Negi when he was under the influence of The World Tree, and an incident involving Akira and a kissing-obsessed golem created by Haruna.
- Midori Days. Tsundere girl Ayase finally admits her love for Seiji, but because she was so angry and tired of not being able to reveal it sooner, she tells him it was just a joke.
- At the end of the Ranma ½ manga, Ranma appears to completely forget his Anguished Declaration of Love to Akane, though whether it's due to deliberate denial or Selective Obliviousness isn't exactly clear.
- In the dub of Yu-Gi-Oh! GX, after Jaden's monsters break out of the Maiden in Love's control:
Avian: What was I thinking?!? I didn't want to get married!Sparkman: Oh, boy... Wait until Sparkwoman hears about this...Both: Guy pact! This didn't happen, okay?
- In Toradora!, Taiga accidentally knocks Ryuuji unconscious into the pool during her competition with Ami, over who Ryuji would hang out with all summer. She's the only one who notices what happens and tries to save him. The screen cuts to Ryuuji regaining consciousness, where we see the whole class huddled far from him, except for Taiga. She's hanging over Ryuuji, not letting anyone else near him, screaming "RYUUJI IS MINE!". Later, when Ami teases her about the incident, she looks like she's gonna properly confess, but simply claims that Ryuuji's her dog and that it's natural to worry over your pet. Ryuuji smiles and Ami gives her an annoyed look.
- Transmetropolitan: Spider Jerusalem & Yelena Rossini get drunk one night. Next morning, Spider wakes up to find himself and her naked in the same bed. Spider contemplates it for a while afterwards and decides to go with the flow, but Yelena goes straight to the trope, and keeps up the charade until the end of series 2 when (in another bout of drunkenness) she loudly confesses to the affair (and to the fact that she wasn't really the niece of Spider's editor) in front of a sizable number of people. The relationship slowly builds again from there.
- Advice and Trust: Subverted in chapter 2. After kissing the night before, Asuka tells Shinji they get to stop. Shinji gets crestfallen, believing she has changed her mind about getting together, but she tells him that was not what she was getting at; she meant they got to stop when other people is around.
- The Child of Love:
- After sleeping with Shinji, Asuka wanted to pretend nothing had happened between them. Since the premise of this story is Asuka going through pregnancy after Shinji got her knocked up, it obviously did not work.
- One week before leaving for France Kaji and Misato slept together. Misato claims she was drunk and wants to pretend it did not happen. No, it did not work very well either.
- Doing It Right This Time: After Gendo and Naoko broke off, she insisted that they pretended that their relationship never happened.
- Evangelion 303: Subverted. After sleeping together for first time Shinji wakes up and notes Asuka is not in the bedroom. He thinks Asuka has left his home and she is going to pretend nothing has happened but he is wrong on both counts.
- HERZ: Several years before the start of the story Kurumi got Shinji drunk in order to seduce him and thus getting together. Unfortunately for her, he considered it a mistake and he would rather forget it ever happened.
- Higher Learning: During a scene where Kaoru is consoling a severely distraught and emotionally devastated Asuka, she kissed him on impulse. She regretted it straight after, got scared and ran away. The next time they met they apologized each other and agreed it was a stupid mistake and it did not happen.
- The One I Love Is: When Misato collapses over the floor after listening to Kaji's last call Shinji hurries to hug her, try to console her and help her to walk to her bed. Accidentally they tripped and Shinji fell on top of her. Misato kissed him before both of them fell asleep. At the next morning both are embarassed and agree to never talk about it again.
- When Harry Met Sally...: After the title characters, previously platonic, have sex without thinking, they try to pretend it never happened the next morning. Realistically, it doesn't work, and the resulting frustration nearly kills their friendship.
- The Philadelphia Story establishes this early on as Tracy's default response to anything crack in her "ivory goddess" self-image. So naturally, when she gets drunk on the eve of her wedding and goes for a late-night swim with Mike...
- In The Mighty Boosh, Howard callously did this to Vince Noir after their Fake-Out Make-Out and the subsequent events in "Party". Howard took the kiss more seriously than Vince had intended, and declared himself gay, telling Vince that he has feelings for him. Vince did not reciprocate, however. Later Howard noticed the girl that he had a crush on and quickly got over it, causing Vince to get jealous and berate him. Howard claimed it to be a 'momentary lapse of judgement.', and asks him not to mention it to anyone. Vince wasn't amused, but quickly got over it when he hooks up with another girl.
- Tasha says this to Data in Star Trek: The Next Generation after an intoxication virus gets them to demonstrate how "fully functional" he is. Subverted in that Data clearly still holds that memory dear, even after Tasha dies.
- A line was cut from Tasha's Meaningful Funeral as well. "Data, it did happen." It's clear to see where it was supposed to be in the script, as they kept Geordi's surprised reaction shot.
- Farscape, after Aeryn and Crichton, thinking they're both going to die in a shuttle with no life-support, start ripping off each other's clothes. After they're rescued, they both excuse it as the stress of near-death conditions, etc. etc.
- Buffy the Vampire Slayer
- Giles has twice done this: once with Joyce (de-inhibition spell) and once with Anya (amnesia spell convinced them they were engaged).
- It also happens, less supernaturally, with Cordelia and Wesley in "Graduation Day" — after almost half a season's worth of flirting and romantic tension, the two kiss twice, passionately... and apparently terribly, because they awkwardly and blatantly ignore it afterwards.
- Likewise when Xander and Willow kiss in "Homecoming".
Xander: (points at her) That didn't just happen!
Willow: No! (gestures nervously) I mean, it did, but it didn't!
- One episode of Hustle required Ash and Stacie to be photographed making out. After the photoshoot, they just stood around awkwardly, trying to be casual. Ash's nickname is Three Socks, after all. This one worked so well because there had never been any subtext between those two, and there hasn't been any since: it truly was just kinda awkward for everyone involved.
- This happens in The Nanny when Mr. Sheffield tells Fran that he loves her in a season-ending cliffhanger episode... then takes it back. The "taking it back" part is dwelt upon ad nauseam for the next season or so.
- This happens in Scrubs with J.D. and Carla. They were drunk at the time and Carla is married to J.D.'s best friend Turk. J.D. insists that it was just a "friend kiss," but Carla denies this was the case. See the kiss in question here and the morning after here.
- Lois is forced to admit that she loves Clark while under duress and hooked up to a lie detector. She later claims to have unhooked herself from the machine and Clark doesn't press the issue.
- When Lois returns from an extended trip and sees Clark for the "first time" after their Almost Kiss at her cousin's wedding:
Clark: Lois, you know, after the wedding things got a little crazy.Lois: Things got a little crazy before all hell broke loose, let's face it. ... Or we could not face it, and just forget that it ever almost happened.
- This actually begins Barney and Robin's Relationship Upgrade in How I Met Your Mother. After an old boyfriend destroys Robin's self-esteem, Barney (displaying his heart of gold) comforts her and gets her to laugh and shrug off the hurt. She takes him home and has sex with him... but the next morning, horrified by the idea that she's become just like the bimbos he sleeps with and brags about, she makes him swear that it never happened. She moves on, safe in the knowledge that they're Just Friends, and oblivious to the fact that he's just fallen in love with her.
- They seem to be awfully fond of this trope. They dated earlier on, broke up, and have since had a few interrupted moments. One evening, after a talk about how happy they are that they didn't get back together and met their respective partners instead, they end up sleeping together. Horrified by what they've done, they decide it didn't happen and certainly didn't mean anything. Barney ends up admitting that it did mean something, but Robin, who's been pining for him up until this point, stays in denial.
- And one last time when they share a drunken kiss a season later. It's later revealed that Barney engineered this one for his Batman Gambit.
- After Shannon and Boone have sex (in flashback) on Lost, Shannon declares that they'll just go back to the way things were before. This is somewhat complicated, considering the two are stepsiblings.
- On Black Books, Bernard thinks he and Fran might've slept together in the past, but he doesn't entirely remember. Suspiciously, Fran has informed that he's not allowed to remember.
- On Dark Angel, Max and Logan have the following conversation after their first kiss:
Max: You know about what happened... I was real emotional with all that was going on.Logan: I know.Max: It's not...Logan: Me, neither.Max: I mean...Logan: Exactly.Max: So long as that's clear.Logan: I'm glad we talked about it.
- Subverted on Northern Exposure: It looks like O'Connel and Fleischman are going to get together on a trip out of town, but O'Connel, running on two days without sleep, falls asleep before they can do the deed. It looks like she's going to forget that the "almost did it" never happened, but she wakes up... and thinks they did it. Then Double Subverted when they return and O'Connel says that she wants them to pretend it never happened.
- Mulder and Scully of The X-Files are this trope. They never specifically say "that didn't happen", but kisses, confessions, conversations, even an invitro attempt come and go and are never mentioned again. They are the couple that never resolves anything. So frustrating.
- Variations on the phrase "this never happened" are Arc Words on Mad Men and sometimes fall into this trope. In season four, after Don sleeps with his secretary Allison and then makes it clear he has no intentions of starting a relationship with her (adding insult to injury by giving her her Christmas bonus the next morning in a manner that obviously makes her feel like a prostitute), she confronts him by telling him, "This actually happened."
- Moonlighting: After David and Maddie's first (non-dream) kiss, this exchange ensues...
Maddie: What was that?Dave: Um...what was what?Maddie: That, that. Weren't you here? What we just did, what was that?Dave: I dunno. I didn't do it. You tell me, what was that?Maddie: What do you mean, 'You tell me'? It wasn't me, it was you.Dave: I didn't do it, you did it.Maddie: I did not do it.Dave: Well I did not do it.Maddie: Well...if you did not do it, and I did not do it, I guess—Both: It didn't happen.
- The Mary Tyler Moore Show has both Mary and her boss Lou become completely squicked out after kissing, leading to this.
- Monk: In "Mr. Monk and the Actor," the main plot is about a Tag-Along Actor named David Ruskin (Stanley Tucci), who will be playing Monk in an in-universe TV film adaptation of the episode "Mr. Monk and the Astronaut." When they have spare time, Captain Stottlemeyer and Lieutenant Disher stop by the set to sit in on the rehearsal. To their embarrassment, the events of the episode are shown way differently from the way they actually happened. It doesn't help that among other things, the producers changed Randy's gender, and created a romantic subplot, resulting in:
Actor playing Captain Stottlemeyer: [talking on prop cell phone and looking off his copy of the script] Uh look, I know he's a bit eccentric, but Adrian Monk is the best damn investigator I've ever had, so you tell the mayor if he goes, I go. [pauses] That's right. [pretends to hang up] Lieutenant Disher! Lieutenant Disher, you got a minute? ["Randy", who is played by a woman(!), comes in the "front door". We are shown a Reaction Shot of the real Randy and Stottlemeyer]Actress playing Randy Disher: [enters] Yes, Captain.Actor playing Captain Stottlemeyer: Uh, what the hell do I say?Stagehand: [from offscreen] The victim.Actor playing Captain Stottlemeyer: The vic, I got it. [reads off his script] The victim, the victim just received a check for $50,000. Pretty weird time to kill yourself. What do you think?Actress playing Randy Disher: I'll tell you what I think. I think the department doesn't appreciate you enough.[gets closer to "Stottlemeyer"]Actor playing Captain Stottlemeyer: Randy, what are you doing?Actress playing Randy Disher: I'm doing what you taught me to do, Captain: following my instincts.[They lean in and kiss. The real Stottlemeyer and Disher are shocked]The real Captain Leland Stottlemeyer: That never happened.The real Lt. Randall Disher: Not even once.Director: SHHH![The actress playing Natalie enters]Actress playing Natalie Teeger: Oh! [clears her throat] Am I interrupting something?Actress playing Randy Disher: I was just, uh, looking for evidence.Actress playing Natalie Teeger: Uh-huh. In his mouth? [calls out the door] Mr. Monk? We're in here.
- The Gin Blossoms did an entire song about this. It's titled "Whitewash" and can be found on the album "Congratulations, I'm Sorry".
- Prince of Persia: The Sands of Time ends with the Prince trying to kiss Farah - but since he rewound time, she doesn't remember how they worked together and warmed up to each other, so she's indignant and offended. Immediately he hits the button on the Dagger of Time, rewinds to before the kiss, and gives the dagger to her - so no, that didn't happen.
- Also spoken word-for-word at the Game Over screen.
- Dragon Age: Origins has the potential for a female PC to end up in a foursome with two members of her party plus another, minor quest character. Should you succeed in pulling it off, the following cut scenes has the female participants asking to "never speak of this again".
- Mass Effect 3: In the game's Citadel DLC, a female Shepard can have a one-night stand with Javik.
Javik: It turns out there is one thing primitives are good at.Shepard: Not a word.
- Happens in Errant Story, after Sarine pounced on Jon (for reasons too complicated to explain here). And unfortunately for Jon, when a 3000-years old magic-wielding Elf decides that something didn't happen, you won't be in any position to disagree.
- Subverted later, though, because Jon remembers just enough to be able to tell that Sarine erased his memory (but he doesn't exactly know why), pressing her to admit that they've "just" done it. Of course, that's more a subversion of Laser-Guided Amnesia than this trope, but still...
- In The Order of the Stick, Haley starts planning denial before the actual kiss. 
- Vaarsuvius sort of pulled this (and revenge, lots of revenge) after Belkar kissed him/her in a drunken stupor during New Years. It helped that Belkar had no memory of 'The Event.'
- This comic shows that at some point, the denial stops being believable.
- In Shortpacked!, Mike sleeps with Amber and Ethan on the same night, in order to drive a wedge between them. Amber's reaction is this trope, Ethan's is quietly asking if he wants to go again.
- Homestuck: We don't know what exactly happened between Karkat and Terezi, and he isn't about to tell us.
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- Sonya and Yuki in Ménage à 3, as seen here.
Sonya: Look, what happened earlier...it didn't happen!
Yuki: And it also didn't happen again in the shower!
- Happened in Hey Arnold! The Movie: Helga revealed to Arnold that she loved him all along and proceeded to kiss him. In the end, they nervously decided that it was because of the moment and nothing serious had happened.
- Danny Phantom:
- Almost a constant in Avatar: The Last Airbender, where the status quo is restored instantly after any change between Aang and Katara. This is most notable after he kisses her during the 'Day of Black Sun', only for the event never to be mentioned, and interaction never changing, for a long period of time. The most jarring instance of this trope, however, happens between 'The Ember Island Players' and the show's finale, where Aang finally confronts Katara with his feelings and is seemingly rejected (and doesn't take it too well), only to find him behaving with her in an extremely normal way the following episode, and jumping straight to a Sealed with a Kiss the one after.
- Invoked in Gravity Falls in the episode "Northwest Mansion Mystery". After Pacifica hugs Dipper from getting caught up in the moment, she then proceeds to pay him to forget it ever happened.
- A downplayed example occurs in the Ever After High episode "Legacy Orchard"; there's no confession, but while Alistair and Bunny are reading a book, their hands brush together- and they look at each other with identical expressions of shock. After a few seconds of mutual awkwardness, Bunny smiles and turns the page, saying nothing.
- Common, particularly among closeted gays, adulterers, and ex-lovers who've broken up but "somehow" fall back into bed with each other. Occasionally the participants agree for things not to happen on a regular basis.