As a guy with no real friends, Nishina Tadadora has spent months just observing Ichinomiya Misumi who sits next to him in class. At first glance, Ichinomiya looks like a lonely girl without any special appeal, but only Nishina knows how sensually provocative she can really be. Upon realizing that Nishina is watching her, Ichinomiya begins to interact with him in her own unique way. But unbeknownst to Nishina, Ichinomiya also seems to be harboring a secret...

She's quite a normal girl with a crush on a handsome boy but she has a hardon everytime she sees him.

Welcome to the life of Haruka-chan, a girl with a penis. Although it's not that uncommon in this world, she is still embarrassed by the fact. There is also a group of dickgirls in the school, and they found out her secret, what will she do?

The woman Tsutomu encounters in college was older and smaller than he is, and for some reason, looks like the same girl in his dreams. The heart-pounding love affair between him and the "older woman" begins.
(Source: Animewaves)

The story begins eight months in the future of the main story, with Nana and Kaoru in the summer of their final year of high school.

It uses a different supporting cast and a different location for the setting, and as such it doesn't really spoil anything from the main series.

Keitaro Satou is 30, successful at his job...and single. With worries about his future, he decides to have an arranged marriage to satisfy himself and his family, yet while his prospective "wife" is a beauty, problems are bound to pop up!
(Source: MangaHelpers)

Kaoru is a 17-year-old virgin who has an SM fetish. He secretly dreams about an SM relationship with his childhood friend Nana. One day Kaoru's mom asks Nana to hide all his SM toys so he'll study for a change. However, Nana finds the leather one-piece that Kaoru bought and tries it on, but she accidentally locks it and doesn't have the key! The beginning of their super strange relationship.

Sakura Uehara, who is 30, has been so devoted to work that she hasn't even dated since high school. Not able to go to university, she went straight to work, and was determined to show everyone she is just as good as those "college assholes" the company values so much. After 12 years in the same company, she has risen to department head, and as luck has it, one of those same college assholes is assigned under her. Yamada is good looking, talented, and on the fast track to success - and destined to be promoted right past her. Of course she ends up hating him.
Letting her pride get the better of her, she takes on an assignment on a tight deadline and has to work late into the night. When a blackout makes her lose her data, she's blows her cool and melts down herself, knowing that there's no way she can make the deadline now. Of course, that's when Yamada comes along, and the two of them working together manage to make it in time. When Sakura tells Yamada she owes him one, he quickly asks to be paid back by having her go out on a date with him. Soon she finds herself in a love hotel with the very asshole she hates so much, but does Yamada have the right stuff to get past her tough exterior and touch her heart?
(Source: Mangahelpers)Included one-shots: Boku ga Seifuku ni Kigaetara, Ohikkoshi Bugi

The story is set in the 90's. Our main character attended a high school in a rural area, and drew his female classmates in his erotic manga. After graduating, he is accepted to a college in Tokyo. There, he finds everything he was looking for - a manga circle.

13-year-old middle school student Sōta Inuzaki (犬崎奏太) comes to stay with 20-year-old university student Eri Inui (犬井絵理) and her mother in Tōkyō to attend violin lessons during summer.