Please Teacher!

The Other Wiki tells us that "Please Teacher! (Japanese: おねがい☆ティーチャー, Hepburn: Onegai Tīchā, Onegai ☆ Teacher) is an anime television series directed by Yasunori Ide, written by Yōsuke Kuroda, and produced by Bandai Visual. It was later adapted into a manga and light novel and centers on a group of friends and the odd things that happen to them after they get a new teacher."

Kei Kusanagi, an Ordinary High School Student, has just seen an alien.

Problem is, she's just announced herself as his new Homeroom teacher, Mizuho Kazami. And she just moved in next door.

And the last time he saw her, she tried to wipe his memory of her existence.

One would think a situation like this would not end well, but a few hijinks later, they end up married, when Kei reveals that he's older than he looks to help keep her position (and to keep a situation from being taken the wrong way).

Unfortunately, now they have to keep his age, her origins, and their marriage a secret from Kei's friends, which is going to be difficult, as one of them is starting to get aggressive in trying to catch Kei's attention.

Please Twins! spun off from this, involving different characters at the same school. Waiting in the Summer is the third anime series of the franchise, with new characters.

Tropes used in Please Teacher! include:

Angst Coma (they have the power to suspend aging)
Anime First
Anticlimactic Parent
Baker's Dozen
Beach Episode - Episode 5, which is also Kei and Mizuho's honeymoon. No one they know is supposed to be there, but of course, Kei's friends and one of the other teachers all just also happened to be there as well...
Bland-Name Product - Famous Brands such as "Pochy". A poster for the movie Titania can also be seen in episode 4.
Bromantic Foil - Hyosuke
But Not Too Foreign - Kaede is one quarter Irish.
Clingy Jealous Girl - Koishi. In episode 3, after hearing Kei may be at Mizuho's apartment, she groans, then heads towards the apartment. Not even Kei's uncle can block her path, and she seems a bit too interested as to why Mizuho would need two toothbrushes and cups in the bathroom if she's living by herself.
- Mizuho in episode 4 spies on Kei and Koishi during their date. She also gets quite upset at him in episode 5 when a random girl yells and cries at him, causing Mizuho to accuse him of seeing that girl, and later spending time with Koishi.
- Konoha, Kei's aunt, acts this way too whenever her husband talks about how jealous he of Kei's romances. She usually hits him since he often says it within hearing range of her.
- Maho isn't too happy that her sister Mizuho is married to Kei either. Although she accepts his relationship later, she steals a kiss from him, while in sight of Mizuho. Mizuho responds by crying.
Chained to a Bed - Happens to Kei in the OVA
Converse with the Unconscious - Happens ALL the time, once with Kei to Ichigo, and quite frequently, Mizuho to Kei.
Cry Cute - Mizuho looks so adorable when she's crying.
Date Peepers - Mizuho spies on Kei during his "date" with Koishi. Ichigo and Kaede also spy on them separately.
Dead Little Sister - The cause of Kei's Standstills
Deliberately Bad Example - Parodied and Lampshaded with Matagu.
Girl, He's Like, In A Coma! - Mizuho kisses Kei for the first time while he's in a standstill (it was Kei's first kiss too!)
Little Miss Snarker - Ichigo.
Love-Obstructing Parents
- Mizuho's little sis Maho is the very model of Obnoxious In Law. Meanwhile, her mom Hatsuho...
Ecchi - This goes to extremes and very very VERY close to hentai in the epilogue episode. So close that anyone that forgets that this isn't an H-anime would probably be disappointed.
Emotionless Girl - Ichigo appears to be so, but she has her reasons...
Fan Service - Clearly. One look at the title character, and no arguments can be made.
First Girl Wins - Mizuho
Half-Human Hybrid - Mizuho and Maho.
Heroes Want Redheads
Henpecked Husband - Minoru, Kei's uncle. Anytime he mentions being jealous of Kei's romances, she tends to hit him.
Hey, It's That Voice! - Mizuho is Belldandy, Nanase and |Sanae.
Hopeless Suitor - Poor Koishi. Her only possible chance would've been to act in episode 1, but after that, it's obvious who Kei is going to have to end up with.
Hot for Student
Hot Shounen Mom - Mizuho's mother, Hatsuho.
- You mean, Hotsuho.
Innocent Fanservice Girl - Perhaps not fully applied given as how each remotely attractive female on the show (that is to say, all of them) has at least some idea of the influence her looks have, but there are plenty of times where they don't realize the effect they have.
Legal Jailbait - Morino Ichigo, 21 years old and stuck in the body of a 15 year old after spending 6 years in a coma.
- Kei as well (though fewer people would care about this since he's a guy); 18 year old in a 15 year old body.
Love Hotels
The Matchmaker - Ichigo
Moment Killer - You'll lose track of how often this happens.
Not What It Looks Like - Used at least once (if not more) in practically every single episode. Not to mention that it basically fuels the plot 90% of the time.
Primal Scene: Done for Maho for humor, possibly due to alien biology causing her to be Older Than They Look. She makes films of Kei and Mizuho's night life and blackmails him using them. Apparently Hatsuho doesn't know this as she does the exact same thing when she sets them up in a Love Hotel and Maho says she wants to see the video chips, which the former says are for "adults only."
- An alternative possibility is that Maho didn't film anything, but Hatsuho told her to blackmail Kei by pretending she had. Maho is shown later asking Hatsuho why her scheme was so elaborate that she actually had a script for it, to which her mother's reply is also rather cryptic. Maho may not have had any idea what was actually supposed to be on the video chips she showed Kei.
Older Than They Look - Kei and Ichigo
Personal Seals
Pixellation
Marie Is Useless - Marie doesn't seem to function well most of the time, such as warping Kei and Mizuho to a wrong area, or not warping at all. Possibly justified, since Kei accidentally knocked her down during Episode 1. Subverted other times when Marie is deliberately not cooperating in order to force Mizuho and Kei to stick with each other.
Relationship Upgrade - Happens to Kaede and Hyosuke
Secret Relationship - Kei and Mizuho can't be open about their marriage largely because it'll be seen the wrong way by both the faculty (aside from the principal who already knows but tells the two not to openly show feelings for each other in public), and Kei's friends. Hilarity Ensues a lot due to this trope.
Shipper on Deck - Ichigo does this for Kei and Koishi. And later Kaede and Hyosuke.
Shout-Out - To Shin Getter Robo Vs. Neo Getter Robo, of all things.
Strong Family Resemblance
Teacher-Student Romance - Obviously the title characters and the plot of the series. Furthermore, they get away with this because not only is Kei really 18 (and therefore legally old enough to marry the teacher), the school principal married a student as soon as she graduated and sympathizes with them. Kei gets creeped out.
The Three Faces of Eve and/or The Hecate Sisters - The heroine, Mizuho, is obviously the "sensible and capable" Maiden, and her "innocent childlike" sister Maho is obviously the Child... but the "Hotter and Sexier" Hatsuho? She's their mother! Talk about Playing with a Trope!
Token Loli - Ichigo
Trademark Favorite Food - Mizuho's "Pochy" sticks.
Twelve-Episode Anime: Including a one-episode OVA.
Twenty Minutes Into the Future - Mizuho's human father was a member of the first attempted manned Mars mission, which is stated to have occurred in 2009. Assuming she ages the same as normal humans, the earliest this series could take place would be the early 2030s.
- Which is weird due to the apparent lack of cellphones.
Wistful Amnesia
X Meets Y - Word of God states that this show is Dustin Hoffman's The Graduate meets My Stepmother Is An Alien.