While most of the example comes from full sentence, this one is notable that it come in two words that is constantly used. Remember Mazinger Z and Great Mazinger? Other than Rocket Punch theres one other weapon that is also popular. Breast Fire and Breast Burner. Yup "Breast" Fire. Then there's the Oppai Missile (Breast Missile)...
Even worse when you include the explanation about Breast Fire's power in series.
And one of the weapons of Great Mazinger is called Navel Missile. It is a huge missile launched from a hatch placed above the robot's crotch...
Nanako: Oh, I'm getting so wet just standing here watching him... I should really go inside where it's not raining.
Everything Maso says is full of unintentional gay innuendo. "Please don't put your fist in me!" and "I know all about men, and men don't bend over without a fight!" to name a few.
Episode 4 of S Cryed introduced George Tatsunami, an agent of HOLY who liked to brag about his Alter, a giant pink revolver called "Big Magnum", with almost every line about it an obvious Double Entendre: "It's big, it's thick, it's hard, and it's coming to get ya!"
FLCL is loaded with Double Entendres of all kinds, both verbal and visual (mainly the latter).
In Spice and Wolf Lawrence and Holo tend to speak to each other in these when they're teasing. Or when they're trying to trick someone.
There was a Fansub where a translator's note appeared in the middle of a long exchange of these saying "Have sex already, goddamnit!"
Grenadier has a few, though they might have been played up a bit more in the fansub. One notable one would be in Episode 5, where Kurenai Touka, the madam of a pleasure palace who is defending it against a gang of gun-toting bandits, says the following:
Touka: If you want to do it, you'll be going against me, boys. Any time, any place, as many times as you want... but if we are going to do it, don't flash me with that tiny thing. Come back with something a bit more impressive.
Two episodes later, Rushuna, stopped at a government checkpoint, admits she doesn't have any identification papers, followed by this exchange:
Guard: S-something smells fishy... Rushuna:(looking confused) What? But I just washed it... (sniffs at her left hand briefly)
Rushuna kind of locks it into a single entendre, but the guard's statement can be taken two ways.
Also, she always talks about removing her enemies' armor. Especially her partner's, Yajiro's, armor, which, considering their apparent attraction, can be taken two ways.
Neon Genesis Evangelion: Episode ten had a particular attachment to the physics term 'thermal expansion'. Asuka was explaining to Shinji what it meant. In a bathing suit. While leaning right over him. And then just drops the whole subtlety and tries to use her breasts as an example (unfortunately being blunt did not help. Shinji yet did not get what she was clumsily trying to seduce him)... Later in the episode, while in the hot springs Shinji hears what sounds suspiciously like Misato molesting Asuka, and starts to blush. Seconds later, he looks down and notices Pen-Pen who's staring at Shinji's crotch with a "what the?!" face. Shinji then quickly submerges to his neck and says "thermal expansion... how embarrassing".
Tengen Toppa Gurren Lagann has this between Yoko and Kittan in episodes 24 and 25. Namely, Yoko was a teacher until recently and mentions that she's going to give everything for her children. Kittan misunderstands this as Yoko being a mother. Yoko answering to his incredulous inquiry with a wink and "A good lady always has some secrets!" doesn't help things either. Her comment about gaining experience by shooting blanks (before her teacherhood, she was a sniper) is just the icing on the cake.
The second issue of Guren Gakuenhen has Kittan remarking that Simon and Nia seem to be pretty good friends; Nia answers that they "performed a husband-wife gattainote "gattai" (がったい）is a noun meaning "combine". so I'm his wife!" Hilarity Ensues as everyone in earshot takes it literally.
School Rumble: Eri asks Tenma if she's ever seen a man's body. Tenma being a Cloudcuckoolander and Eri not being specific results in some confusion. (Tenma later thinks they were talking about wrestling, and she replies with "yes" cries to "taking it in the mouth" and such.) Teehee. Also in the series, Mikoto is thinking of a plan to get her and Imadori back to the shore, and thinks of several plans, including Plan D, which involves using Imadori as a boat. She asks Imadori what plan he'll take, and he takes D gladly. Mikoto is at first surprised by this because it's the most dangerous, but then it turns out that he was just guessing Mikoto's breast size.
Tsukino subverts this. When Ken convinces Suwabara not to commit seppuku by telling him that Monica was pregnant, Ken says "when a man and a woman are living in the same house alone, there is nothing for them to do except—" She completes the sentence saying "play cards, right, Manager?"
Later played straight during the Yakitate 25 arc when Azuma and the gang are making a soft bread and their opponent is making a hard bread. Tsukino turns to the manager and says, "Between a hard and soft bread its obvious that hard is better, right?" To which Ken replies, "That's your preference as a woman..." He is shirtless and she is wearing a bikini at the time to make it more suggestive.
Momoko from Shangri-la speaks almost entirely in double entendres.
When Nnoitra asks Ulquiorra how far he's gotten in ""taming" Orihime, Ulquiorra was not at all amused.
In anime filler, Ichigo and Renji scuffle outside the classroom when Ichigo tries to force Renji to take off his gigai. He doesn't actually say that, however, he keeps yelling "Take it off!" until his classmates rush to see what's happening and find Ichigo pinning Renji to the ground apparently trying to tear off Renji's clothing. The class all reach the obvious conclusion.
Hisagi has "69" tattooed to his face which is a source of endless fandom jokes. There is a (mostly) innocent in-universe explanation, but Tite Kubo admitted in an interview that he deliberately wanted a double-entendre for adults that children wouldn't understand because he was amused by the idea of parents being too embarrassed to explain it to their kids. There's a reason the fanbase has nicknamed name him "The Trolling Creator".
The fact that it's told that several nations do share the same bed in the anime version of Axis Powers Hetalia is enough to hint at something more... but a rather clear example of it occurs during a rather memorable over-the-phone conversation between the brothers Italy and Germany... which turned out to simply be their hair getting tangled up.
Italia Veneziano: Germany! Germany! Save me! I'm on my bed now and my brother is— OWW!! It's stuck! Owowowowowow!! Italia Romano: N-Not there!! Put down the phone, you idiot!! Italia Veneziano: Take it out! Take it out!! Italia Romano: Put it down!! *click* *dial tone* Germany:* long pause* ... His brother is... Stuck... "Oww"... Take it out...
Considering the hairs in question are called 'erogenous zones' outright in the manga? This scene takes on a whole new meaning.
The time Prussia invaded Austria's vital regions
Greece and Japan's so-called "private lesson?" We saw the morning after, with Japan, besides Greece in a bed, curiously shirtless...
Then there's this in the Christmas episode:
China: We're not allowed to have Christmas trees because they're flammable. It kind of sucks.
Italy: Heh, just like the girls.
Chapter 13 of Ai Kora is largely an exercise in double entendres and dirty Japanese wordplay when Maeda realizes how much of a thrill he gets out of hearing Kirino say dirty things in that husky voice of hers. In Chapter 40, when Kirino tries to compose an original song, Maeda tricks her into performing a song laden with yet more double entendres. Then he does it again in Chapters 55 and 56, when he convinces Kirino to sing in a punk rock band (then weasels his way into the band himself). And again in Chapter 92, when Kirino tries out for a role in a movie musical. You'd think he would have learned by now...
In one chapter of the Yu-Gi-Oh! manga, Yugi is explaining to Jounouchi how to exchange information between their digital pets, so that they can grow stronger. In doing so, he uses the word "gattai", which means both "combination" and "copulation". Jounouchi answers saying that their pets must "kouhai", that means "cross-fertilize" or "mate". Next to them, Honda warns them that people might hear them and misunderstand.
The English version translated this as Jounouchi saying "Alright, Yugi! Let's you and I mate [our virtual pets] right away!" and Honda complaining "I didn't need to hear that..."
Non-sexual example. The first words out of Luffy's mouth in the broadcast Funimation dub of One Piece were "That was fun, but I don't think I wanna go back there." In the show, he was talking about a dimensional ship graveyard the crew had just encountered. But coming off the previous dub which was handled by 4Kids, it was absolutely hilarious to the long suffering English fans.
Crocodile makes one when he's threatening to dehydrate Vivi:
Crocodile: Want to become a mummy?
Also, during Luffy's second fight with Crocodile:
"His right hand is nothing to laugh at."
Another nod to the Funimation dub. A citizen of Water 7, watching Franky write and cry in agony, says, "That scream! It almost sounds like someone is choking a chicken to death!" Considering Franky's screaming is due to Robin's powers having him, literally, by the balls, it's quite an appropriately-funny line.
At one point in the Zombie Powder manga, Gamma's opponent demands that he "pull out his piece". When Gamma draws his sword, he holds it upwards at a forty-five degree angle from his crotch.
In a rare instance of a dub being noticeably funnier than a direct translation, the English dub of the first episode of Burn Up Excess features Maya preparing for a firefight, cooing, "Oh Hideo, you're so hard and long. Just a little while and I'll let you shoot your whole load, I promise." Who's Hideo? Her handgun.
Episode 3 of Afro Samurai shows our protagonist relentlessly pursued by a robot. When it's about to drop dead, it unleashes all its remaining energy in one final laser cannon blast that is barely averted. There a lot of phallic connotation to it, from the shape of the cannon (both before and after it fires) to the sidekick's quip once it's finally down: "I think he blew his load." That last double entendre actually harks back to the historical origins of the term "blowing your load" (the complete and proper firing of guns).
In the trailer for episode 2 of Chrono Crusade, Rosette goes on about how she's going to lose something precious, carrying on about it (without providing any actual description to the item being lost) to the point where one would think she's going to end up losing her virginity. In the episode itself, it turns out the precious something she loses is her gun.
Getter Robo: "If there's a hole, it's a man's job to thrust into it!" He's talking about traveling through wormholes, we swear.
The anime version of Crest of the Stars has a scene with dialogue between the main hero and heroine: "Be gentle" and "It's my first time", complete with heavy breathing. In reality they are crash landing on a enemy occupied planet- it's her first time landing a spaceship, and the heavy breathing is due to G-forces.
In Bubblegum Crisis: Tokyo 2040, Linna attempts to explain why she wants to stay in Tokyo (actually to stay with the Knight Sabers, an incognito superteam, but she can't say that), but if you take the dialogue at face value, it sounds more like she's awkwardly trying to come out to her very traditional mother. Considering the amount of Les Yay between herself and other lead character Priss, there's rather considerable debate on whether this is actually exactlywhat it sounds like.
One volume of XXX Holic opens with Watanuki asking "Really... no problem?" with Yuuko seductively replying "None, Watanuki. Come on. As hard as you like..." Cue the baseball pitch.
In Macross Frontier, Sheryl once comments that "Implants are common on Galaxy", but she is "all Natural". What she means are brain implants, like built-in cameras etc. However it sounds more like... "something else".
It wasn't Al's intention, but in the Second Raid OVA his commentary of the combat situation he's running for Souske applies perfectly to what the half-naked, drunk Tessa is doing.
Lisa of Popcorn Avatar is fond of saying things that can easily be misunderstood by other people. Whether she's doing this on purpose begs to be revealed.
A rather audacious example was seen in Yuyushiki, when Yuzuko and Yukari fantasize about Yui's "delicious little bean." Certainly this is a reference to the natto Yui served them earlier that episode, but the way they reacted to that may make viewers wonder if they're talking about a certain part of the female anatomy.
Ojisan And Marshmallow, episode two, has Wakabayashi-san offer Hige-san a marshmallow while he's on the phone with their boss (explaining that they're caught in the rain and are going to be late). Except she doesn't mention the word "marshmallow" and is loud enough to be heard on the other end.
"You can lick, suck, and bite on my 'you-know-what'...."
And Hige-san's unthinking response? "I'm on the phone at the moment. I'll gobble it up later."