Happens to Lafiel in episode 6 of Crest of the Stars. Ironically, she's a guest of an Abh noble, and she's the granddaughter of the Abh Empress, and doesn't realize she's being held at the time.
Happens to Tsukushi in the second Hana Yori Dango episode, when she's brought to Doumyouji's Big Fancy House. IIRC, it involved Tsukushi believing he wanted to rape her and slapping him around until he explains that he just wanted to have his maids change her ruined clothes.
Happens to Negi in Mahou Sensei Negima! when he visits Evangeline, who happened to be bathing at the time. His complaints are mostly because he doesn't like washing.
This was done to Sarasa in the last episode (ep. 13) of Legend of Basara. (see above picture)
At the end of Fushigi Yuugi, we learn that this was Nakago's fate under the emperor of Kutou.
Andrew Waltfeld has this done to Cagalli in Gundam SEED after an assassination attempt on Andrew left Cagalli with food all over her. It doesn't have villainous overtones, however: although Andrew is Cagalli's sworn enemy, he pretends he doesn't know who Cagalli is or that she's after his life, and was actually being genuinely affable; not surprising, given the Grey and Gray Morality of the Gundam franchise.
The Obsidian Lord orders his female Dragons to do this to Mai after he's done using More than Mind Control on her in the manga version of Mai-HiME. Very creepy since he's using her younger brother Takumi's body as his vessel.
In a Catwoman comic book, before her wedding to a nobleman, the title character was forcibly given a bath by two of his henchwomen.
In X-Treme X-Men, interdimensional conqueror Kahn captures Storm and intends to make her his bride, and has his servants bathe her.
Inverted in the furry comic, Xanadu, when Tabbe Le Fauve is captured. The unicorn Empress Alicia orders him bathed in the magic unicorn pool. Being a cat, Tabbe is frantically resistant to be thrown into water, but immediately changes his mind when he is thrown in: the magic water feels more like silk and Empress Alicia, naked, smoking hot looking and horny as her horn, climbs in to join him.
Has happened to Red Sonja more than once, when some Evil Overlord decides to make her part of his harem. See the Sonja Goes East one-shot for one such example.
Happens in Little Ego when Ego is taken to the harem of the Green Sheik.
In the Naruto fanfic Duty Before Honor, Sakura is subject to this when she goes undercover to retrieve a vase from a dirty old pervert. Unfortunately, this washes off most of the poison she smeared over her body to protect herself from said pervert.
The Prince of Egypt has an example-by-proxy of this. Tzipporah, a Midian woman who was kidnapped by the Egyptians and given Ramses as a concubine, is passed off to Moses, who tricks her into falling into a pool of water. Ramses gives the order, "Dry her off and have her sent to Prince Moses' chambers!" Moses doesn't look any happier with the thought than Tzipporah, but she swiftly enacts her own escape before any awkward confrontations can occur.
Funnily enough, this is Inverted later—he winds up in Midian after wandering in the desert and is bathed by some old women. He seems just as uncomfortable as before.
This happened to Bo Derek as "Jane," in the 1980s version of Tarzan (starring Miles O'Keefe), as she was captured by generic African savages and prepared as the royal bride for their chief.
Non-villain double subversion: after Eliza Doolittle from My Fair Lady agrees to the experiment, Higgins orders Mrs. Pearce to bathe Eliza and to burn her old clothes. Eliza, apparently aware of this trope, fights back like a wild cat, very... insistent that she is not "that kind of a girl".
In the book, Pickering, being Genre Savvy, takes this moment and makes Higgins promise that he won't exploit Eliza's position (in that way). Higgins assures him that this he would never exploit his student. (Well almost never...)
Paradise (1982) had a fairly straightforward example of this trope, though it seems contrived mainly so that the villain's incompetence would keep him from having his way with the heroine before her heroic boyfriend could rescue her.
In the Film Prince Valiant, this happens to Lady Jane. She is bathed by the other captured princesses.
The Colonel orders this done to the two Mexican girls he intends to rape in The Warrior's Way.
In the campy 1980 classic Flash Gordon, Ming The Merciless orders his lackeys to "Remove the Earth woman" (Dale Arden) and "Prepare her for our pleasure" just after using his hypnotic ring to seduce her.
Literature
In Slave World, this is not merely common: It is a social institution surrounded by all kinds of rules and protocols.
A male version in the Belgariad: Salmissra sends the kidnapped (and drugged) Garion off with her maidservants to be bathed.
Happened in Shadows of the Empire, when Prince Xizor was both trapping Princess Leia and teasing her with possibilities of an alliance while attempting to seduce her. She was his guest for a while, and explicitly dressed in the dark so it would be harder for him to spy on her. He once invited her to take a bath with him. She got back at him later.
Inverted in the Anne Rice novel, Blackwood Farm. After being kidnapped by Petronia, Quinn Blackwood awakes to find a pair of servants bathing him in preparation for his vampiric conversion. They even go so far as to give him a haircut and a shave before bringing him before Petronia. The rest of the event unfolds in a less pleasant fashion as Petronia has Quinn fight her in a hopeless battle for his own life where Quinn eventually attempts a Groin Attack. Petronia then forces Quinn to fellate her hermaphroditic penis, which he does...just before he bites down hard. The blood from that bite is what eventually forces Quinn into vampirism.
Functions as a semi-important detail in the novella The Wager Lost by Winning (part of John Brunner's Traveller in Black series), where the rather unsympathetic protagonist is bathed before being claimed by Lord Fellian.
Fool's Fate, the last book of Robin Hobb's Tawny Man trilogy, has the hero brought before the big bad as she bathes. She then gets out of the bath in a seductive manner and leaves him to relax in her still hot, used bath water. Given that he's been worn ragged searching through ice caves and frozen wasteland for the past few weeks, he resignedly accepts.
In The Hollow Kingdom, Kate gets this treatment right before her wedding to the goblin king.
Another male example is Orson Scott Card's novel Hart's Hope, when Orem is prepared for his first meeting with Beauty.
In The Baker's Boy, Melli is at one point captured by one of the Big Bads and offered a bath, which he subsequently watches through a hole in the wall with delight.
In George R. R. Martin's The Sworn Sword it is sarcastically noted that the name of this trope could just as well have been the personal motto of the late and infamous womanizer king Aegon the Unworthy.
The Blackadder Chronicles included a transcript of Captain Darling's application form for Emergency Transfer to Somewhere Much Safer. At the bottom were three checkboxes for the superior officer to choose between: "Application approved"; "Applicant to be Shot at Dawn"; and "Applicant to be washed and sent to my tent".
In Jason Cosmo, the hero comes from a muddy little village where bathing is frowned on. When he tries to enter the town of Whiteswab, he gets pounced on by three guardsmen wielding wire brushes and soap.
In Jacqueline Carey's Kushiel's Chosen, every time Melisande comes to visit Phedre's cell on La Dolorosa, the latter is forced to wash and don clean clothes before she arrives.
When Amara of Codex Alera is captured by Brencis Kalarus Minorus, he collars her and taunts/questions her, complete with maidservant doing the washing, while she's being cleaned in the bath. This being a Jim Butcher work, though, of course it's actually a ploy, as she made herself immune to collaring by being pre-collared by her husband/spy-partner around her thigh, hiding it under her pants, and went into the situation expecting to probably be captured so that she can get close enough to make a (successful) attempt on Brencis' life.
In A Song of Ice and Fire, Ramsay Bolton takes this to the next level with his bride. He's a bit of a hygiene freak, and has her constantly bathed.
A non-villain (but still Jerkass) example is Spellfall: Natalie, a 12 years old girl, is captured by an evil Wizard Hawk, and after a few days of capture, escapes with Merlin, Hawk's son , who is 11 years old. When they arrive at the Council of Oq, she is told that before she can speak with the council, she has to take a swim in a special pool. As she herself also desires to be clean, she is actually glad - until she learns that Merlin also has to take a swim in the same pool, and no, bathing suits are not provided...
Live-Action TV
On Lost, Kate is offered a shower and a change of clothes when she, Jack and Sawyer are captured by the Others. However, it's slightly subverted in that her jailer tells her that she's "not his type".
"Have her scrubbed and brought to my tent." John Cleese appearing on Cheers.
Referenced in QI, where the sight of Alan Davies trying on a scold's bridle brought on the Ho Yay:
Alan Davies (as Stephen Fry): Have him scrubbed and brought to my room. Stephen Fry: Actually, don't bother to have him scrubbed.
Arms dealer Mezentius says this in the Xena: Warrior Princess episode "The Path Not Taken", instructing his guards to have a female captive "bathed and perfumed and brought to my chamber".
This happened in the Robin of Sherwood episode The Betrayal in which Prince John repeats the trope almost word-for-word in regards to Marion, telling her she'll be bathed, scented, dressed in Byzantine silk, and brought to him.
In the Mötley Crüe's music video "Too Young to Fall in Love", a young, dirty homeless woman is taken in by some kind of secret underground kung fu clan. She is then bathed to look presentable for the leader.
Something like this appears to be happening in the video for Lady Gaga's "Bad Romance".
Myths & Religion
Older Than Feudalism: See the Book of Esther in The Bible, where concubines of the king must spend months in a bathing regimen before they go to his bed.
Video Games
In Metal Gear Solid: Peace Walker, Dr Strangelove captures Cécile, but takes pity on her and treats her well, with particular emphasis on giving her sponge baths every day (when Snake asks why, Strangelove responds that she was just "admiring her beauty"). Played with somewhat in that Cécile seems to enjoy the attention and teases Snake with the mental image.
Generals in Medieval II: Total War may use a similar line in their pre-battle speech. "And if you happen to find a young lass in their ranks, wash her and bring her to my tent!"
Web Comics
Inverted in Darths & Droids, where Pete (playing as R2-D2) demands as his reward for saving the Queen's ship to be cleaned and oiled by the most beautiful handmaiden.