A sequel to Please Teacher!, Please Twins! (Onegai Twins!) centers on Maiku Kamishiro, who moves into town looking for his childhood home, showed in a picture of him playing with his long-lost sister. He soon meets two young girls, Miina Miyafuji and Karen Onodera, who both also have the same picture. But there are only two kids in the picture, and neither of them know which is the sister. To make matters worse, both girls become rather attached to Maiku.
The series, of course, includes appearances by the characters of the previous series, showing how they've fared since the end of Onegai Teacher. It is also notable for being the first work in the long-running partnership/friendship between voice actresses Mai Nakahara and Ai Shimizu.
- Absurdly Powerful Student Council: Ichigo seems to be in total control of the school, to the point of being able to take a bunch of students on a tropical vacation on student council funds. Or give Maiku a job. Lampshaded in the novel by mentioning that many students and staff liken her to Adolf Hitler in how she manipulates and abuses her power.
- A-Cup Angst: Miina feels insecure about her bust size way despite not being that small. She's flat, but not as flat as Karen; she puts it as she'd rather be flat than at an in between flat and average size.
- Alliterative Name: Miina Miyafuji and Yuka Yashiro anyone?
- Ambiguously Bi: Kousei has feelings for Tsubaki and the two are dating, but he's openly flirted with Maiku and even once attempted to kiss him, claiming they were bonded by the red thread of fate; it's entirely possible he only does this to annoy Maiku, it works.
- Blatant Lies: Ichigo, often. Also Miina in this priceless moment◊.
- Bridal Carry: Maiku has carried both Karen and Miina this way, he carried Karen this way in episode 1 when she passed out upon seeing him and Miina not fully dressed (Miina in just an oversized t-shirt and Maiku just got out of the bath and only clad in a towel) and he carried Miina like this in episode 7 when her injury acted up and she couldn't walk.
- Brother–Sister Incest:
- This is the main reason why Karen and Miina don't act on their feelings towards Maiku because of the possibility they are related to him. Though novelization and anime adaptation switch who is the canon, true twin, and chosen girl at the end. However, in the light novel, both Karen and Miina are related to Maiku, Miina is Maiku's twin sister, while Karen is Maiku and Miina's first cousin. So in the novels, incest is inevitable if Maiku gets with either girl. The manga changes how they find out who is the true twin, but the same girl ends up the twin as in the anime.
- Also with Matagu, who didn't have any particular lust for his sister in Please Teacher!.
- Catchphrase: "We might be related! We might be strangers!"
- Childhood Friend Romance:
- Maiku and Miina in the anime and manga.
- Tsubaki and Kousei, sort of, they've known each other for awhile and dated for awhile.
- Clingy Jealous Girl: Karen becomes this to Maiku in the OVA, after discovering she's his sister, she becomes scared that if he and Miina start a relationship, she'll become less important to him, so she interferes with any attempts at them being intimate.Karen: Maiku is my big brother, and mine alone.
- Conveniently an Orphan: Maiku, Karen, and Miina are all orphans, their birth certificates made once they were found and put in orphanages, so they can't tell who is the twin from birthday because none of them know their actual birthday; so they really have to rely on their shared eye color and photograph as the determining factors of them being twins.
- Cool Code of Source: Several episodes have what appears to be C++ , plus some program showing a hex dump.
- Curtains Match the Windows: Maiku; blue hair and blue eyes.
- Demoted to Extra: Several cast members crossing over from Please Teacher! go through this, but none more so than Kei—the poor guy doesn't have a single spoken line! (Except in the OVA).
- Evil Laugh: Ichigo's delightful "Ufufu", complete with a Cat Smile.
- Faint in Shock: Karen fainting at any surprise or stress is a running gag, though like many such things, it tapers off as the series goes on. Becomes a bit less amusing when you consider the parent series, Please Teacher!, which had a condition called Standstill, in which a person can spend years in a coma-like condition (without aging) after too much extreme emotion. One of these days, Karen might not wake up for a long time...
- Fanservice: Truckloads of it, since the two girls share their baths all the time.
- Flanderization: Matagu. He was a pretty normal guy in Please Teacher! but has been flanderized into an incestuous creepy paedophile in this.
- Flat Character: Matagu, despite being much more rounded in Please Teacher!.
- "Friends" Rent Control: For an orphaned high school student working to support himself, Maiku's house is pretty big and fancy. Then again, the small-town setting makes this slightly less unrealistic than it would be in an urban setting. It's also explained that Maiku discovered the house in less-than-perfect condition and was able to rent it cheaply.
- Fully-Clothed Nudity: The ending of the OVA shows Maiku in his briefs after Karen accidentally spills coffee on his pants and Miina revealing her bra. Both of which shock everyone at the campsite except Ichigo, who happily takes a picture of the scene.
- Genki Girl: Miina
- Imagine Spot: All three of them keep having fantasies about each other. Including guilty ones such as Samurai-Karin and Cop-Miina (each by the other)...
- Imagine Spotting: And upbraiding each other over them.
- I'm a Man; I Can't Help It: Kousei's excuse for having touched Tsubaki's breasts when they first kissed. At least this is what he says to Maiku.
- Incompatible Orientation: Played for Laughs, since, while they're both straight, Miina and Karen got into a particular situation once that Miina interpreted as a pass on her.
- Jerk with a Heart of Gold: Maiku, he's first reluctant to let the girls stay, but eventually lets them and he does talk to them, usually Miina, rather cruelly.(Miina suddenly trips)
Karen: Are you okay, Miina-san?
Maiku: Why did you trip? You're so stupid.
- Little Miss Snarker: Ichigo Morino, as mentioned above.Mizuho-sensei: What are you doing?
Mizuho-sensei: You're lying, aren't you?
Ichigo: Well of course I am.
- Long-Lost Relative: The plot of the series is that either Karen and Miina may be Maiku's twin sister and the series is spent trying to figure out which one it is. It is discovered that Karen is Maiku's sister, but the other kid in the photograph is Miina. In the Light Novels, the other girl that is not the twin in the anime and manga is the twin, while the girl that is the twin in the anime and manga is Maiku's first cousin.
- Love at First Sight: Like in the previous series, the little girl with the dog at the beach spots Maiku and immediately starts swooning over him, only to get heartbroken when Karen and Miina show up.
- Luminescent Blush: Maiku, Karen, and Miina are all highly prone to this; Miina and Karen even more so.
- Mistaken for Gay:
- Because Maiku hasn't been ogling them, Karen and Miina worry he is gay. So they crank up the Fanservice level to try and get a reaction out of him.
- Classmate Kousei Shimazaki constantly flirting with Maiku, on top of being the closest thing he has to a friend at the school, doesn't help matters. Karen and Miina might not have mistaken Maiku's sexuality at all in not for female classmates fantasizing about the two of them as a couple.
- No Periods, Period: When Karen is brooding over her revelation, the other girls assume that it is her time of the month.
- Nosebleed: Poor Matagu!
- Not What It Looks Like: Karen just fainted and fell face first into Maiku's lap, honest!
- Oblivious to Love: Maiku; he's completely unaware of Miina and Karen's love pact and Tsubaki's feelings for him.Miina: Man is he dense.
- Official Couple:
- Maiku and Miina by the end of the anime and manga.
- Tsubaki and Kousei were one prior to the series, but Tsubaki broke up with him because of him being a pervert, they get back together close to the end of the series.
- Kei Kusanagi and Kazami Mizuho. While it was secret at Please Teacher!, after 2 years the fact is so well-known they no one bats an eye when Kei and Mizuho share a tent and she left a lipstick mark on Kei's face.
- Older Than They Look: Ichigo, 23 years old and stuck in the body of a 15-year-old after spending 6 years in a coma.
- While Karen looks a bit young for a 15-year-old, her more childlike personality really starts to show in the OVA. Her voice in the dub doesn't really help either.
- One Head Taller: Maiku is a full head taller than Karen, while he's only about half a head taller than Miina.
- "On the Next Episode of..." Catch-Phrase: "Next time, more twins!"
- Orphan's Plot Trinket: Maiku, Miina, and Karen each has a photograph of Maiku and his sister in their hometown. Unfortunately it doesn't mention the sister's name.
- Plot-Based Photograph Obfuscation: A convenient hat obscures the hair color of the girl in the photograph. In the manga, Miina looks at Maiku's copy of the picture; since his was framed, Miina could see the color of the girl in the photo's hair due to the brightness and noticed that the girl's hair was pink, meaning the girl in the picture and the non-relative is Miina.
- Pretty Freeloaders: Miina and Karen qualify as this until they get roped into attending school and working.
- Red Herring: In the series' big twist, the photo is deliberately misleading- the girl in the photo is Miina, but she's not Maiku's sister, Karen is. She's just having a nap off-camera. Also, they realise the house they're living in is actually the one in the background of the photo, and they're playing at a neighbor's house (that of Karen's family).
- Right for the Wrong Reasons: Seeing the photo of a boy and girl playing outside the house, Maiku, Karen and Mina conclude that one girl is his sister and the other unrelated. Technically they're right, but the picture was not of Maiku and his sister. It was of him and the neighbor, while his sister was inside. It never occurred to them that the third girl might just be outside of the picture but still connected, or that the picture might not be an indication of relation.
- Sacred First Kiss: Kousei botched it for Tsubaki by groping her breasts, leading to their breakup before the series' start.
- Scenery Porn: for those who like small-town Japan.
- Sensei-chan: Mizuho, even moreso than in her original series.
- Shrinking Violet: Karen the shy, quiet, ill girl.
- Teamwork Seduction: Mina and Karen team up for an episode to seduce Maiku in a mistaken attempt to turn him straight.
- Title Drop: Both parts of the catchphrase listed above are episode titles.
- Tomboy and Girly Girl: Miina's Tomboy to Karen's Girly Girl.
- Twincest: Although no true sexual contact occurs between any of the three main characters until they figure out who is the real twin. Until then, it's only affectionate hand holding and light kissing.
- Two-Teacher School: Lampshaded when a student mentions that it seems like the school only has two teachers (Kazami Mizuho and Yamada Masaomi).
- Wouldn't Hit a Girl: Maiku beats up only Kousei when he, Tsubaki, Ichigo, and Kazami watched his and Miina's First Kiss, saying he couldn't raise a hand against his teacher or sempai and that Kousei would be the representative for all of them.