Think Unsexy Thoughts

Sometimes, a man doesn't want to have an erection. Either it's potentially physically hazardous, or there's a beautiful woman who he actually wants to spend time with and turning up with an obvious case of wood might not help. (Or of course, both.) Or maybe he's just embarrassed to be seen in public that way. And sometimes, a man might be in the act, so to speak, and in need of some way to delay the inevitable.

Either way, the solution is the same - to conjure up some image in the brain that draws attention away from the contents of the pants. Such an image is either hilariously mundane or hilariously horrific. In American media the former option often takes the form "Think about baseball!"

The opposite of Lie Back and Think of England when used for sex. Fetish Retardant and The Loins Sleep Tonight are inversions of this.

No real life examples, please; we'd be here all day.

Examples of Think Unsexy Thoughts include:

Anime and Manga

In Infinite Stratos, Ichika finds himself in a changing room with Charlotte, after she pulled him in both to hide from the other girls following them, as well as to show him the outfit she planned to wear at the beach. With his back turned to her, as he hears her undressing, he forces himself to recite Pi in order to get his mind off thinking about her naked body. It eventually works, but a few moments later they get caught...by his older sister and homeroom teacher.
In Fullmetal Alchemist: Brotherhood, Ed is with Winry and trying not to think of the time Hawkeye teased him about being in love with her, and starts spouting out the periodic table.
In one chapter of A.I. Love You, Hitoshi has been forced into a pair of underwear that will slap him in the crotch whenever he stirs and will explode if it reaches thirty slaps. He tries to avoid getting whacked by thinking about male body builders...while peeking in on the girls' locker room. (Un)fortunately, he loses focus for a second, the underwear slaps him, and the sound alerts the girls, who beat him up.

Comic Books

Rudi does this one time at a nude beach. Problem is that everything he tries to think of only makes him more horny. ("Square root of 4761 makes... 69! Shit, maths is too perverted!") Then, when he finally manages to get his Raging Stiffie under control (by thinking about cancer) - a pissed-of wasp stings him several times in a male body part, making things even worse.

Fan Works

There is an NGE fanfic where Shinji tries to summon this trope... then decides he went too far with it and stops. What did he think of? His father in a thong.
- I think this is It Can't Get Worse by Zentrodie, its on the Neon Genesis Evangelion fanfic page.
A Pirates of the Caribbean fanfic has Will using the "Margaret Thatcher naked on a cold day" version after a Parody Sue gives him a love potion. He has to spend a lot of time chanting, but it works. Jack, his fellow captive, has no idea who he's talking about but is impressed all the same.
One Ranma ½ fanfic has a bit more of a PG version of this. After being challenged by Akane to not blush no matter what she does to him (No, it wasn't a lemon), Ranma tries to prevent himself from blushing by imagining Cologne in a string bikini.
- A lemon has Ranma think about martial arts and mentally go through several katas in order to not come before Akane.
An X Files comedy fic has Mulder in the middle of a meeting and daydreaming when he sees Scully eating a banana and his imagination starts generating some very NSFW daydreams. He exuses himself to the bathroom and goes through a variety of possibilities (baseball, some of the cases he worked), until his thought process stumbles on the idea of the Cigarette Smoking Man naked. Mulder is relieved not be turned on anymore, but really wants to wash the mental image away with a beer.

Film - Live-Action

Austin Powers combines this with a Survival Mantra: "Margaret Thatcher NAKED ON A COLD DAY! MARGARET THATCHER NAKED ON A COLD DAY!"
In the Steve Martin movie All of Me, a woman is stuck in the body of the main character. He wants to sleep with another female character, but his 'roommate' objects and starts filling his head with images of dead kittens and old nuns.
The title character of Blankman routinely goes into... convulsions... when kissed or otherwise aroused. "Think about math..."
Margaret Thatcher again serves as anti-erection fodder in Bedrooms and Hallways, where Leo, a gay man, is convinced to sit in a sauna with the fellow (straight) members of his support group.
In the movie The Couch Trip John Burns, who is posing as a psychiatrist, recommends thinking of transmission repair for this purpose. Unfortunately, his description of taking apart a transmission, though he doesn't seem to realize or intend it, does not exactly qualify as unsexy. Observe: http://www.youtube.com/watch?v=8SQNjg982JQ

Literature

In the novel Choke, the protagonist thinks of corpses and other disgusting things to avoid early ejaculation.
In Stephen King's IT, Tom Rogan thinks of "White Sox batting averages or who was trying to undercut him for the Chesley account at work" for the same reason.
In Going Postal, Moist von Lipwig finds himself in this mindset regarding Adora Belle Dearheart. "He'd get another chance to be smiled at by Miss Dearheart -- think about Golems! Golems, golems, golems!"
In Dave Barry's Complete Guide to Guys, Barry inclues advice for men on how to delay their orgasms, and suggests thinking of Margaret Thatcher, or, in extreme cases, Rush Limbaugh in a thong.

Live-Action TV

Anwar from Skins recites Hugh Grant's filmography in order to slow himself down.
In the That '70s Show episode "Thanksgiving", Eric has to do this after making out with an attractive girl. His inner monologue goes: "Okay, baseball, Vietnam, Richard Nixon, Pat Nixon, Pat Boone, the girl that gives the weather, no, no! Okay, jellyfish, really big spiders, come on, dig deep, dig deep, okay, the day we backed over Skipper in the driveway, instead of going to the county fair, I had to bury him in the backyard."
- Inverted later with Donna who thinks of sexy things.
In Kyle XY, Josh explained to Kyle that when he doesn't want to have an erection, he thinks of "disgusting things" (for him, zits and old people). Kyle responds that he finds grapefruit disgusting (Josh: "Huh."). Later in the episode, he repeated that phrase while escaping naked from the parents of the girl he was with.
- "Zits. Old people. Zits. Old people. GRAPEFRUIT!"
A Running Gag on Glee is Finn thinking of the time he ran over a mailman in order to prevent himself... arriving early.
- It's made a plot point on "Never Been Kissed" when Sam needs to find his "mailman" and decides to think of Coach Bieste in various unflattering positions. It's so effective that the method spreads-in fact, it's too effective, soon the boys (and Tina) actually start saying Bieste's name during makeout sessions, causing their partners to become suspicious. And then Bieste finds out, and things get very unfunny. That's right, Glee actually deconstructed the trope.
In an episode of Melissa & Joey, Joey has to constantly call his mom in order to distract him from having sexual thoughts about a friend of Melissa.
In the Married... with Children episode "What I Did for Love", Jefferson mentions that there was a time when he had to think about baseball to slow things down during sex; nowadays, he just wants to think about baseball.
- In another episode Steve thanks Al, because wondering why Steve Guttenberg is a star works as this.
In an episode of Friends, Joey mentions "baseball, or sandwiches, or... Chandler" as things he thinks of to keep himself from getting too "excited".
- Phoebe tries to follow his advice, but finds even baseball and sandwiches too sexy... thinking about Chandler, on the other hand, works fine.
- In another episode Ross gets rid of an erection by thinking about his grandmother.
In the Dollhouse episode "Needs," Victor plays the baseball flavor of this trope straight and out loud during the shower scene, reciting the Mets roster by fielding position after catching a glimpse of Sierra.
Wonder Woman TV Series: After immortal Princess Diana of Paradise Island invokes What Is This Thing You Call Love? when he sees a man for the first time, her mother hilariously invokes this trope:

Queen Hippolyte: There are some things that are better not known. Young Amazon minds are best occupied with athletic discipline, higher learning.

In the Boy Meets World episode "The Last Temptation of Cory", Cory mutters the words "lunchroom lady" to get him to stop thinking about a pretty girl who is trying to seduce him away from Topanga.

Video Games

One of the members of the band Love Fist in Grand Theft Auto: San Andreas is a chronic masturbator. To get him to stop, his bandmate tells him to "Think of Thatcher". Unfortunately, that just turns him on more.

Web Comics

Slick from Sinfest has to work really hard at this when he gets a hug from Monique.
SSDD has this, when a guy has to go without sex for a while. Being around computer nerds, unsexy thoughts aren't hard to come by.
Saturday Morning Breakfast Cereal has a number of takes on this

"Oh, Steve! What gives you such amazing stamina?"
"The boundary conditions of the universe."

The Pain - When Will It End has one comic, "Silver Linings of the Holocaust". The first example is "Excellent Sexual Endurance Aid", where the man is thinking of the atrocities committed in concentration camps to keep from going off early. Then his thoughts stumble across Ilsa, She Wolf of the SS, and, well...

"ARBEIT MACHT FREI!"

Western Animation

Family Guy's Quagmire was subjected to "aversion therapy" to try and discourage him from being such a pervert, which involved a ceiling fan perched right above his groin and a Victoria's Secret catalogue. His attempts to contain himself involved thinking of dead kittens, old nuns, really old nuns, and Renee Zellweger.
To try to keep from being aroused by a sexy new coworker, Homer Simpson imagines his disgusting sisters-in-law Patty and Selma wearing towels and shaving their legs in the bathroom as well as his best friend Barney Gumbel in a polka-dot bikini drunkenly humming the theme to I Dream of Jeannie. Doesn't work, as Barney morphs into the sexy worker. His mantra is the Trope Namer.
- Bears mentioning that the object of Homer's crush also had this mantra when she was near Homer.
An episode of John Callahan's Quads had the main character think about his ugly nun teacher in order to help him maintain an erection... because the unsexy thoughts would help him with premature ejaculation.