The most popular way to brag, to confess to someone you've cheated on, or to answer an angry parent who has asked, "How did this happen?", as a way to avoid going into all the details no one really wants to know. If this is how someone (optimistically) plans to get someone into bed, it's a Missing Steps Plan - Step One, Boy Meets Girl; Step Two: ???; Step Three: Coitus Ensues!
Don't Try This at Home, needless to say.
Not to be confused with Halfway Plot Switch.
- In Dragon Ball Future Trunks sums up Bulma and Vegeta's relationship as "...and then she saw my father sitting there so proud and lonely and then one thing just led to another."
- Fate/kaleid liner PRISMA☆ILLYA 2wei chapter 16. Judging by Luvia's Imagine Spot, she hopes to eventually have a child and marry Shirou using this method.
- Takes place between Shiho and Chiomi in Private Actress, doubling as Rescue Romance.
- A Crown of Stars: Shinji and Asuka took a shower together a short while after their Love Confession. They were going to wash each other's backs and they weren't planning on having sex, but then they started kissing, and eventually Shinji was pinning Asuka against the bath wall while they humped each other.
- This is more or less how Toji and Hikari's offscreen Relationship Upgrade went down (literally!) in Doing It Right This Time:
- Discussed in A Brother's Price: Jerin doesn't want to do anything that could be considered sexual (like kissing) with a woman, because he knows that one thing could lead to another, and he has to remain chaste to marry well. (Sexually transmitted diseases are a serious danger in that world.)
- In A Song of Ice and Fire, Robb ends up breaking a marriage treaty because of this, which has very unpleasant consequences later (just like everything else in the series).
- The Wheel of Time: This is how Rand Al'Thor falls for two of his three love interests.
- Decorated with numerous lampshades in William Goldman's early novel Boys and Girls Together, where Jenny actually says at one point, "In a book it'd say 'their lips met' and then there'd be a double paragraph break and a line of stars," whereupon— their lips meet, and there's a double paragraph break and a line of stars to imply that the characters had sex.
- A non-humorous version in Harry Turtledove's second World War novel Tilting the Balance, as Barbara Larssen's explanation to her husband of how she and Sam Yeager first ended up sleeping together in the first novel. The phrase is used verbatim. In her defense, she had reason to believe he was dead, and she and Sam had just very narrowly escaped being killed, while a soldier next to them was not so lucky.
- In the Mary Russell novels by Laurie R King, Russell's narration uses this dodge as a Sexy Discretion Shot when she and her husband Sherlock Holmes are about to engage in hot monkey marital relations.
- In the novel "To Sir, with Love", Pam's mother name-drops this trope when explaining her and her daughter's estrangement, admitting that she invited a friend of hers over for tea, "one thing led to another and he decided to stay the night. . .", thus revealing that Pam is upset with her because she walked in on them.
- In The Secret History, Richard Papen achieves this in the narration with the blunt "Matters progressed." (They don't progress that far, however, as a third party walks in and interrupts.)
- Frequently heard on Law & Order: Special Victims Unit. A pregnant teenaged girl pleads, "We never meant for it to happen, it just did." An ex-boyfriend recalls, "We shared a glass of wine, one thing led to another, next thing I knew, we were in bed." A teacher who raped a 12-year-old boy defends herself:
Meredith Rice: He was crying. I followed him to make sure he was okay. One thing led to another... Next thing I know, we're having sex.Detective Stabler: And that seems like a perfectly natural segue to you?
- Used by the model six Cylon in Battlestar Galactica: Razor in describing how she got involved with Admiral Cain.
- Round the Twist, when Pete tries to explain to his father the strange supernatural twist of the week.
Pete: I met this girl and, and one thing led to another...Linda: I think what Pete is trying to say is, he got her pregnant!Pete: No! She got me pregnant!
- Hunter. An ex-girlfriend describes to Dee Dee McCall how she once got involved with Hunter by saying, "This led to this, that led to that..."
- In an episode of Friends, it is revealed that when Ross was in high school, he made out with the school librarian. (who was much older than him) When asked how it happened, he replies: "I was working late in the library one afternoon. It was just the two of us. She needed some help with her word jumble. And one thing led to another..."
- In the episode "The Contest", George uses the phrase to describe how he ended up masturbating in his parents' house: "I stopped by the house to drop the car off, and I went inside for a few minutes.. Nobody was there - they're supposed to be working. My mother had a Glamour magazine, I started leafing through it... So, one thing led to another..."
- It also uses a similar phrase, "Yada Yada Yada," to describe a mysterious lead-up to strange or sexy events.
George Costanza: So Listen to this. Marcy comes up and she tells me her ex-boyfriend was over late last night, and "yada yada yada, I'm really tired today." You don't think she yada yada'd sex.
Elaine: (Raising hand) I've yada yada'd sex.
Elaine: Yeah. I met this lawyer, we went out to dinner, I had the lobster bisque, we went back to my place, Yada Yada Yada, I never heard from him again.
Jerry: But you yada yada'd over the best part!
Elaine: No, I mentioned the bisque.
- In The Fresh Prince of Bel-Air, Will gets seduced by his girlfriend's mother, while she was trying to start a fling with Uncle Phil. To keep the same from happening to Phil (caring, not cock blocking), Will takes Phil aside to warn him:
Will: And then she slipped into something more comfortable, and she's showing me pictures of San-- San something, and then, you know, before I knew it... you know... Ta-dow.Phil: Tadow?Will: You know, "taaaa-DOW".Phil: ''"taaaaaaaaaaaaa..."-oh!-OH! YOU SLEPT WITH JANICE?!
- The Big Bang Theory
Leonard: Okay, let me try it this way, uh, I was at a coffee klatch with a couple of friends and one thing led to another and it turns out you're off the team.
- Brian Regan:
I hate when you're trying to read something and you come across the expression "One thing led to another". What in the hell kind of lazy writing is that? Isn't that your job as the writer to tell me how this led to that? You can just throw that in there? "Adolf Hitler was rejected as a young man on his application to art school. One thing led to another... and the United States dropped two atomic bombs on the sovereign nation of Japan." "This is some pamphlet!"
- Rose says this about her relationship with Roy Campbell in Metal Gear Solid 4: Guns of the Patriots. And she would say that, as she doesn't really have a relationship with Campbell, it's all just a cover to keep Rose and her (and Raiden's) child safe from The Patriots
- Strongly implied to happen between Kent and Fiora from Fire Emblem: The Blazing Blade if their support chain is completed. The hilarious part is that the two were meeting to try and cut down on unprofessional fraternization within their army. Clearly, it didn't work.
- Parodied in the Homestar Runner toon "Pumpkin Carve-Nival", where the King of Town tries to explain how his Jack-O-Lantern entry turned into a partially-eaten pumpkin pie.
- Pokemon Pals: Misty gets charmed by a man at a bar, who claims that she was the reason he got into Pokemon. They end up sleeping together offscreen. He disappeared the next day.
- In an episode of Futurama:
Amy: Well, the car broke down on Mercury, and one thing led to another...Fry: ...and then it led there again when we got back home
- Used in Guardians of the Galaxy (2015) for Getting Crap Past the Radar . Peter meets his dad, J'Son. J'Son talks about meeting Peter's mother, him living with her for a while, etc. Peter Squicks out pretty hard as soon as the trope name comes up.