In the Pokémon series, the Day Care Man refers to Pokémon mating as "playing", as in "[Your Pokémon] would prefer to play with other Pokémon than each other."
Justified in that said daycare man is talking to a 12-year-old.
Interestingly, in the Next Generation Bionic Commando two tidbits go on the opposite direction. Once, prior to facing a boss, Super Joe tells you that "There's no way around [the boss], you'll just have to fight.", to which Spencer replies "My pleasure". However, if you die and try again, Super Joe tells "you'll just have to fuck it", leaving us with a puzzled "Hmmmm...?" response.
Then, later, on a less humorous stance, Spencer is mumblimb about how the last boss 'shouldn't have messed' with him. Again, if you die, it becomes 'shouldn't have fucked' with him.
A meta-example in the Dwarf Fortresscommunity — "Fun", derived from the motto of the game, "Losing is Fun", and always capitalized. It can be both used to refer to the act of losing ("I'm having a lot of Fun right now,") and factors that are likely to make you lose ("I just embarked in a particularly Funevil biome.")
The "Hidden Fun Stuff". But certain parts of the community got tired of that, and when DF 2010 came out, produced a suite of Unusual Euphemisms: getting some "cotton candy", going to "the circus", and meeting "clowns".
There's also a moogle in Final Fantasy XII: Revenant Wings that spouts out a long string of 'kupo'. Not entirely coincidentally, said moogle has the name "Foul-mouthed Moogle".
The fact that it's the rough equivalent to "poo-poo" in Polish is probably a coincidence. The name of the perennial Super Mario Bros. villains caused a certain amount of hilarity in that part of the world for the same reason.
You spoony bard! This line has gotten so iconic that it's been lampooned countless times and always included in every remake of Final Fantasy IV even when the entire script has been rewritten (so far it's happened twice).
Son of a submariner! One of the few times where the euphemism makes more sense than the word it's replacing.
This may be most famous from FF 6, but I was familiar with the expression when I first played the game - a librarian I knew said it from time to time before the game was ever made. Submariners definitely have a reputation even compared to other navy personnel for coming into port ready to do something or other that might result in having a son, with any female without much regard to attractiveness, temperament, etc.. Still, they chose to use it...
Sly 3: Honor Among Thieves had a level inhabited with pirates who came up with some rather amusing insults rather than traditional profanity. The title character even lampshades this at one point.
In a probably unintentional example - being a game targeted to a younger audience - within the game Mechquest, there was a holiday event in which you could go into a house where a randomized NPC would say a rumor about your character. One included: "I heard that *your character name* does somersaults with Nurse Helia!" Nurse Helia is female, if you were wondering. Or maybe Freud Was Right in just my case.
In the MMORPGPuzzle Pirates, the game client allowed three settings for filtering swear words: Leave them unfiltered, turn them into %* $#@! and the like, or "Pirate-ize" them, making them acceptable terms. This generated such phrases as, "We're all scuppered." Even the simple acronym "wtf" would be translated into "Blistering blue barnacles!" - a Shout-Out to Tintin.
For certain sexual terms, the "Pirate-ize" filter will substitute "John Thomas" and "harmonica lesson". The full list is available here.
Miscreants like Garrett are called "taffers" in the world of Thief. Lower-class citizens use variants on this word, making sure nobody is "taffing about", "taffing with me", or "giving me taff". Though fans of the series speculated that "taffer" was derived from some real word from a European culture the universe resembled, the creators assures us the word was made up.
The term 'space' (as a verb) is sometimes used in Sci-fi as shorthand for the act of ejecting something from an airlock, e.g. in one episode of Babylon 5 wherein an alien ship is said to have 'spaced' the captives held on board.
Another term from the same games is "Schutta." If the Exile asks Atton what it means, he replies, "Ask a Twi'lek. It's not flattering."
There are some other fun ones for the sex act. "Just because I saved her doesn't mean I'm going to go charging up her boarding ramp!" "You look like you and [your Love Interest] just hooked up a power coupling" (for that last one, you can ask "What do you mean?", and Mira replies "You know! Hooked up a power coupling?" A more obscure example referencing the previous game is "Pulling a Bindo," which apparently means leaving the Jedi. The expression is a Shout-Out to the first KOTOR game, when NPC Jolee Bindo did just that.
Specifically : leaving the Jedi to be with a woman (since Jedi are Shaolin monks IN SPACE, and thus supposed to be celibate)
In Star Wars: Republic Commando, Boss likes to demand "What in Death's name?", and when telling his squad to blow stuff up he says things like "Let's rearrange some architecture, Deltas," and "Initiate radical restructuring, Commando." He also once says "By the Force!" and "BLAST!" After that last one, his most rulebound squadmate asks "What's that, sir? I didn't copy" and is told "Uh, just some interference on the comlink."
The original Wing Commander used "slag off" as an Unusual Euphemism for less Media Watchdog-friendly terms ending in "off". Unfortunately, as to slag someone off means to insult them, "slag off!" is equivalent to shouting "insult!"
Marcia of Fire Emblem: Path of Radiance has used the following words as expletives: crackers, chestnuts, mutton chops, horsemeat, jerky, and barnacles. She's just as colorful when coming up with an insulting term for someone.
In fact, Fire Emblem is full of this stuff. "Moldy onions" and "hornet hairs" in particular stand out.
The word "Frag" is used to mean a kill in an online FPS. See Live-Action TV examples below.
Frag is short for "fragment", or "tear into pieces". So not really less graphic. It may mean a more difficult, more graphic type of kill, in some games.
In Zork: Grand Inquisitor, Yoruk is an ancient and powerful wizard, so powerful in fact that wars have been fought over the possession of his skull. (And yes, this is a Shout-Out to Hamlet.) As such, people use the term "Sweet Yoruk!" in the same way people in real life use "Sweet Jesus!" (though they say "Sweet Yoruk" more than people in real life say "Sweet Jesus". When was the last time you heard someone say "Sweet Jesus"?)
Also, the people in Zork get milk from Hunguses instead of cows, so "Holy Cow!" becomes "Holy Hungus!"
Math-obsessed Minamimoto in The World Ends with You flings mathematical terms instead of profanity, most commonly "hectopascals" and "you zetta sons of digits". This is most obvious near the end, when he clearly replaces the F-word with "factor" (especially since "factoring hectopascals" makes no sense as it's a measurement of pressure).
Eiji Oji, an in-game celebrity, has a blog called "F everything," and its title may you to believe it's a stereotypical angst-filled blog...until you discover that to "F" something means to declare it to be "fabulous."
"F this ramen! F it to high heaven!"
The Sims 2 has pairs of Sims "Woohoo", rather than have sex. Used consistently, though the original The Sims would only have "Play" in similar contexts.
Fans of the game has since adopted it as their own euphemism.
In The Sims Medieval, pirate town Aarbyville is also known for its "meat trade." This is actually an Unusual Euphemism for prostitution, though it takes a few references before you get it. (The Fighters' Guild quest has perhaps the most transparent one.)
In Days of Ruin an unnamed IDS agent uses terms such as "Oh good gravy" and "Sweet corn casserole!". This and her other funny dialog (such as being the only one to care that the plane they are on is crashing) is key in framing the theme of the breather chapter she appears in.
Her dialog is completely straight faced and purely expository in Dark Conflict
One of the Naughty Sorceress' attacks in Kingdom of Loathing refers to cooking you up "a nice spaghetti breakfast." This is an euphemism one of the game staff uses for tentacle rape.
This euphemism was originally shared with the founders of the game 1000BlankWhiteCards.
In Reality Breakdown: Kel's War, the third game in the Reality Breakdown series and the first to happen chronologically, protagonist Kel's home dimension seems a bit different from most other dimensions, in that they use energy from the sun to perform their "magic", and have "frap" as a swear word. The word is versatile, too, as one NPC is seen running into town yelling "One frapping huge army is coming!", while another time Kel wakes up and asks a party member how long he was out. When hearing how many days he was unconscious, he says "frap, I missed the weekend". Amusingly, Kel uses the word in another dimension later in the game, and naturally no one knows what he's talking about. The word is likely a combination of "fuck" and "crap".
Interesting combination, as "fuck" and "crap" are two words on opposite sides of the swear scale (with "shit" being about between them, but leaning slightly more to the "fuck" side of the scale). Of the five most common expletives, they rank fuck, shit, crap, damn, ass. Just check most TV programs. Censorship seems to only allow swears up to a certain level of the scale depending on the program, and likely the time it's on. Futurama will allow crap, damn, and ass (lots of ass), but not shit or fuck. They say "bastard" a few times, though.
An NPC in Happy Happy Village in EarthBound tells Ness, "Don't go to heaven!" This piece of dialog sounds like Nintendo of America put it in as an oddly censored version of "go to hell," but it was present in the Japanese version as well.
There's also the memorable, "You will be gone, and you'll be burning in...well, you'll go to heaven!"
In Dragon Age: Origins, Alistair will ask the player character in they've ever "licked a lamp post in the winter." In context, this becomes a euphemism for sex...or something. Also, Oghren will ask "Where can I get some sauce for that rump roast?"
There is also a rather hilarious exchange between Alistair and Oghren about "polishing their swords." Whether or not this is in fact a euphemism or not is lost on everyone, including Alistair.
Oghren seems to be a master of these, as evidence by this conversation, again with Alistair:
Oghren: So. With the boss, aye?
Oghren: You and the boss. Rolling your oats.
Alistair: I don't know—
Oghren: Polishing the footstones.
Alistair: —what you're—
Oghren: Tapping the midnight still, if you will.
Alistair: what are you going on about?
Oghren: Forging the moaning statue. Bucking the forbidden horse. Donning the velvet hat.
Alistair: Are you just making these up right now?
Oghren: Nope. Been saving 'em.
Oghren also drunkenly mistakes the PC for his ex-wife's female lover, referring to her as a "moss-biting poetess." Sort of the dwarf equivalent of "carpet-munching," one would assume.
Also subverted in a conversation the Warden can have with Zevran:
Zevran: You know, all this talk of Antiva, and for all it's riches and adventure, it is the leather I miss the most.
Zevran: *Laughs* It may as well be! But not this once, no.
The sequel continues the fun with filthy-minded party member Isabela, who utters a similar series of euphemisms asking if Aveline and Donnic have had sex and how good it was. "Put it in your peach" is one memorable one; she also uses "mastered your taint," riffing on an unintentionally humorous line from the first game that underwent Memetic Mutation.
BioWare seems to be quite fond of this trope (among many, many others), as in the Lair of the Shadow Broker DLC for Mass Effect 2, we had this exchange.
Shepard:(looking at a giant screen with asari dancers) What kind of hotel is this?
Liara: Azure. It's a luxury resort with an... "exotic" edge. "Azure" is slang for a part of the asari body in some areas of Illium.
Liara: In the lower reaches - near the bottom.
Shepard: I meant "where on the asari body".
Liara: So did I.
Played with in the second game during Garrus' romance. After his loyalty quest, he mentions how turians "blow off steam" before high-risk missions (also leading to a gem along the lines of "I had the reach, she had the flexibility"). When Shepard suggests casual sex in the same manner, he agrees to research it so neither of them go into shock from exchanging incompatible fluids. After referring to it in very scientific terms and mentioning how terrible that sounds, he goes back to "blowing off steam".
The Commander Keen fandom often uses "fucl", although it's not actually used as a euphemism in the games. It comes from an Easter Egg in which a few platforms on one level spell out "FUCL", but it's obvious what the developers ment, and soon became a meme.
In Fatal Fury 3, when you play as Mai Shiranui in a single player game, the pre-battle conversation with Andy Bogard includes this line:
Andy: W...What?! Mai, what in the name of the Great Ice Cream Salesman are you doing here?
In Paper Mario, Koopa Koot shouts quite a variety of these (mostly involving enemy characters) when Mario completes favors for him. "Great galloping Goombas!" and "Suffering Shy Guys!" to name a few.
Sengoku Rance replaces every instance of the word "penis" with "hyper-weapon" and uses "imperial juice" as a euphemism. Which leads to...
Rance's hyper weapon is ready for action!
In The Witcher 2: Assassins of Kings it seems to be a common euphemism to replace the verb "fuck" with "plough", as in "Go plough yourself!" As a standard exclamation "fuck" is still liberally used in the game
One of the Harvest Moon games has the term "Best Friend system" when to the lesbian marriage option. You "best friend" your 'friend' even though they clearly have both Affection and Friendship points once you get a certain item, and that the clearly affectionate lines are all left in from the original male-only version of the game.
In the middle of Halo: Reach, Kat comes up with a highly unconventional plan to take out an enemy super-carrier.
In Blaze Union, when the girls of the party reject a gaggle of gangsters propositioning them, the gangsters decide to use force where words wouldn't work, and declare "Im Taking You Home With Me" before attacking. Explicit use of the word "rape" would probably have forced a higher CERO rating on the game, but more importantly, it would have destroyed the over-the-top nature of the scene and taken away all that remained of its humor value.
One of the questions on the G.O.A.T. character-design test in Fallout 3 is, "A crazed vault scientist runs up to you and yells 'I'm going to stick my quantum harmonizer in your photonic resonation chamber!' How do you respond?" It's a euphemism for something, but we're not quite sure what.
And oddly enough, the obvious answer isn't on the list of responses. "Up yours" is, however.
Near the end of the Namek storyline in Dragon Ball Z: Supersonic Warriors, the narrator says that Krillin, who was defeated by Freeza, was nowhere to be found.
During the opening of Portal 2 when Wheatley is moving your bedroom, he tell's you he's going to "attempt a manual override on a wall". Translation: He is going to bang your bedroom against it until it goes through the wall!
In the Mists of Pandaria expansion to World of Warcraft the Hozen frequently use "ook", "grook", and "dooker" (and variants) in ways to quite obviously suggest they are swear words.
A prime example: "I'm gonna ook you in the dooker!" No, really. It's actually said.
In Cataclysm..."THRALL'S BALLS!!!" which has become memetic as of now due to it's hilarity.
At the end of Resident Evil 4, Ashley apparently ends up swooning over her heroic savior (i.e. Leon), judging by her propositioning him for "overtime".
In Tales of Xillia, Teepo uses the word "bazongas" to refer to breasts (Which is made apparent if you don't cook anything for a while, which may prompt him to say Elise will never grow any if she doesn't eat). Jude is shown to be unaware of the meaning in a skit, where Alvin and Rowen decide to take advantage of it for their amusement by goading him into yelling "TEACH ME ABOUT BAZONGAS!" at the top of his lungs, which gets him a scolding from Leia.
Umineko: When They Cry has Shannon and Kanon refer to themselves as "furniture". This seems to be a way of illustrating the class difference between themselves and their love interests, who are members of the family they serve, and how (in Kanon's case), they have no right to be with them. The truth is actually even sadder.