In Ah! My Goddess, Urd turns the tide of a softball match by showing up in a uniform two sizes too small without a bra, destroying the focus of the all-male team she and the rest of the cast were playing against.
In After School Sex Slave Club one of the cheerleaders/sex slaves is told not to wear any underwear during a baseball match. The opposing team lost by paying too much attention to her.
Happens a lot to Maeda in Ai Kora, who has a tendency to go nuts for any woman who has at least one of what he considers "ideal parts". So far the only girls in his "harem" to consciously manipulate this fact are Ayame and Yukari.
In Bayonetta: Bloody Fate, Luka sneaks into Bayonetta's hotel room while she and Cereza are bathing to poke through her stuff. When the pair step out of the bathroom, the sight of Bayonetta's naked body makes him stumble over his words and then stumble out the window.
Black Butler has Ciel invoke this during the cricket tournament when his Blue House team is up against the much more physically fit Green House team. He has Lau and his female employees lounge just off the field in the Green team's line of sight, with the ladies all dressed to expose their legs — which, given the Victorian setting, is the equivalent of walking around topless. It works perfectly, completely throwing off the Green team's players until security throws Lau's group off the field.
Bleach: Orihime Inoue inadvertently has and uses this on occasion. It actually becomes a minor plot device in the Xcution arc when Shishigawara can't kill her because she's so over-the-top attractive. All he gets for his troubles is a massive nosebleed and a crush on her. Its even mentioned earlier in the arc by several of the male students who say she's the most popular female student at the school because of this trope.
In Busou Renkin, when Tokiko is forced to wear a two-piece bathing suit, she spends the whole long beach scene chewing out other people whom she accuses of staring at her bellybutton. She even yells at the readers.
In Change 123, this trope is played (at least) twice:
Ozuma, during the judo match with Mikiri, suddenly sees that under her judo-gi Mikiri has nothing but some skimpy underwear. She quickly manages to score a small point because of his distraction.
On the sports festival at school, during the "battle on horses", Hibiki and Ginga jump towards Izuru to take away her headband. Izuru manages to evade Hibiki's hand, and so instead of the headband, Hibiki tears away Izuru's clothes. This results in Hibiki's and Ginga's "horses" to be distracted by Izuru's breasts, and so unable to catch their "riders".
Cutey Honey: Honey Kisaragi used this as one of her weapons. Although sometimes her transforming device worked wrong and she did it accidentally.
Don't Become an Otaku, Shinozaki-san!: When trying to covertly put a doujin she borrowed from her brother back in his room, Akina comes across a yuri doujin and stops to flip through it.
During his fight with Jackie Chun in the same tournament, Krillin decides the only way to beat a Dirty Old Man is to...throw a pair of Bulma's panties at him and kick the old pervert while he's distracted.
He's not the first great warrior (or the last) to be brought low by a girl's panties—
This was Bulma's problem. She tended to go gaga over any hunk she sees, which is a problem when they're the bad guys. Halfway through Z, this was dropped.
Double Subverted in Dragons Rioting, where protagonist Rintaro has a rare medical condition that means he could die if he gets sexually aroused. From a young age, he was trained intensively in martial arts and meditation specifically to keep himself focused and detached from sexual desires. Unfortunately, while attempting to get himself transferred to an all-boys school to avoid temptation, he ends up in a school with a vastly majority-female student body, most of whom tend to be a Ms. Fanservice of one type or another. So while he tries to avoid it as much as possible, he definitely notices all the sexy around him.
Rintaro: Clear mind, silent and serene heart.
Durarara!! has a rather unusual recurring example: Anri herself doesn't have any notable attraction to Shizuo Heiwajima, but the Evil Weapon that she serves as a host to is completely Yandere for him. As a result, Anri's mind is flooded with obsessive thoughts and... uncomfortable physical sensations when she so much as looks at him, and she has to concentrate to push them down.
Fairy Tail: This happens to Juvia in a side chapter where she's supposed to be using her magic as a water slide attraction for Lucy, who ends up tumbling ungracefully into the water when Juvia sees Gray's "glorious body".
Happen in the episode 19 of the sport animeGanbare Kickers where the titular soccer-team challenge an all-female team where the all girls wear short skirts. With the exception of Daichi, the main character, the boys are easily distracted during the game.
In Get Backers, this happens when Himiko and Hevn are imprisoned by Makubex's henchmen during Limitless Fortress arc. At some point, two prison guards enter their cell and start ogling them. All of sudden, Himiko opens her jacket, revealing her nearly naked body (justified because her clothes are heavily damaged by Akame and her jacket, taken from a random mook, is unbuttoned and barely covers her modesty), and asks the prison guards to scratch her itchy back. The prison guards gleefully accept her request after seeing her almost naked body. Turns out that Himiko is tricking them to inhale the puppet perfume soaked on her body, in order to force the guards to undo her handcuffs, along with Hevn’s. Seen here.
And in episode 11, Amu got her clothes torn. She took advantage of her nakedness to distract several soldiers and allowing Leccee ambush them.
In JoJo's Bizarre Adventure, when the heroes try to get to the cockpit of the soon-to-crash airliner they're on, they are stopped by a couple of flight attendants... only for said flight attendants to immediately get distracted by Jotaro.
Later, in Diamond is Unbreakable, Jotaro has trouble getting Josuke's mom to answer his questions, as she's too busy Eating the Eye Candy to pay attention to what he's saying.
In Maison Ikkoku, Yusaku Godai often gets distracted fantasizing about Kyoko, causing him to fall down/run into things/kiss inanimate objects.
Happen often when Aki. In the episode 4 she herself say at Takeru and Unsui to focus the mind and avoid distractions while she wear her classic skimpy outfit. And they start to fantasyze on her in bikini.
Chapter 63 has Aki help Takeru for his homework. He has really difficult to focus with Aki that wear only a shirt and short pants.
Takeru: (now with nosebleed) "How HOT. Why isn't she changing?"
Uruchi usually only has eyes for Haruko, but the sight of Love Espada bending over onstage in a Playboy Bunny costume was too provocative even for her to ignore. It caused her to get a nosebleed as well, and had to be snapped out of it by Takaki ordering her and the others to take Espada off the stage.
It happened fairly often in the manga. Usually was Sayaka the one did the unwilling distraction — either because her clothes were torn or because she was involuntarily naked —, but sometimes it was done by enemies to distract Kouji. Like the Gamia sisters...
One of those scenes was animated in Mazinkaiser. In the Beach Episode, Sayaka storms up to the Mooks to give them a piece of her mind, and Kouji accidentally yanks off her top when he tries to grab her shoulder to stop her. Once he notices that the Iron Masks are totally entranced by Sayaka's boobs, he actually weaponizes it, pulling her arms away every time they encounter more Iron Masks, then knocking them out while they're drooling. Sayaka, for her part, is more upset about Boss seeing her than she is about being used this way.
Great Mazinger: Just how many times Boss ran into an obstacle because he saw Jun walking by and he stopped looking forward while he walked?
Weaponised in Naruto by the titular character's Sexy Jutsu. Note that victims of this include prominent ninja like Jiraiya and the Third Hokage. Even Sakura and Kaguya aka the rabbit goddess fell victim to a Sexy Jutsu involving a harem of naked men during battle!
In one episode of Panty & Stocking with Garterbelt, Panty and Stocking go job hunting. One part of the job montage features them directing traffic, but their tight cop outfits cause more accidents than the girls prevent, pictured above.
During a festival centering around Oshawott, Ash's Oshawott is using Aqua Jet during an event. One glimpse at his crush, Osharina, caused him to lose control and crash into his trainer head first.
One episode has Chespin having to run an errand for Clemont. Chespin continually ends up distracted along the way and one of the gags involved it being distracted by a Marill riding with its owner on a bike.
More like mesmerized in Kiyoshi's case from Prison School. In an arm-wrestling match with Meiko he spots her nipple due to her being unaware of having a nip slip. He's so enamored by the sight, it puts him in a dazed state, where he doesn't even realize Meiko had already won the match.
Ranma ˝: Arguably, Happousai's only weakness is he is easily distracted by girls' underwear or girls in various states of undress.
Sayonara, Zetsubou-Sensei has a segment on this (or rather, getting distracted in general, and forgetting the point of what you're watching) that involves an invading alien leader getting completely sidetracked from his invasion by gratuitous fanservice... which the viewer is also shown, and which generally does succeed in distracting the viewer from the actual plot until the next obvious reminder. Other non-sexy distractions include showing the credits onscreen at moderately high speed without stopping the action or dialogue in any way. It works, too.
Blair the Cat from Soul Eater uses this for comic relief AND in battle.
Then inverts it in the chapter of lust when she's turned into a man, and is STILL smoking hot to the opposite sex.
In Star Driver, this happens to Okamoto during her fight with Takuto. Much to the disbelief of the observers. And her opponent.
In Toradora!, this was Played for Drama as all the boys were too distracted looking at Ami in her bikini to notice that Ryuugi was accidentally knocked out and fell into the pool, leaving Taiga (who cannot swim) to go after him. She promptly calls the boys out for their behavior.
Particularly hilarious example in Vipter GTS. Ogawa summons a succubusto put a curse on the students who picked on him. But when he lays eyes on Carrera , he promptly ditches that idea in favor of having sex with her. Carrera takes it in stride and figures, 'sure, why not?'
Happened in Yes! Pretty Cure 5 concerning the school reporter. Whenever it's possible the girls were caught on camera, Mr. Natts would show up and she'd focus more on him than the girls in terms of article importance.