From ShoujoMagic:

All Kumiko wants is to become a teacher; however her father is dead set against it. He is giving her one chance to prove herself as a teacher before forbidding her from pursuing this career forever. Meet her newest student, Ryu-kun. He has NO desire to LEARN anything from his tutors, rather he is an expert at teaching THEM about...SEX?!

Note: The story was originally released as a single short story, but it later became a series.

From 801 Media:

Being with an older lover is hot on just so many levels... Seiji-kun is a novice manga artist. He's also completely addicted to the body of the incredibly beautiful Sono-san, despite the fact that Sono-san is a guy. Is this love? Along with the title story, one that paints a tale of youth and emotion, this volume is filled to the brim with stories of overwhelming density, including "Not Just When it's Convenient" and "Let's Go Home." A total of six stories in all.

• Onegai dakara, Kiss (w)o Shite (Please, Kiss Me)

• Otona no Tsugou ja Naikute (Non-Adult Situations)

• Gaki wa Sunao ja nee (Indirect Youth)

• Aiganbutsu wa Oheya no Naka (Trophies Belong in the Bedroom)

• Ouchi e Kaerou (Come Home)

Midori Yamate is a 15 year-old girl and is very much a tomboy. When she was young, Midori meets a boy called Tsukasa Hino, who came to the island she lives on for a holiday. He teaches her to play soccer and she falls in love with the sport. Midori is inspired by Tsukasa and continues to play soccer in hopes that they would meet again someday. When they do meet again Tsukasa does something unforgivable. Determined to defeat Tsukasa on the soccer field Midori enrolls in an all boy high school.

Contains a short story of 2 chapters called Shounen x Cinderella in the 8th and 9th Volumes:
Sakuragi Azuma has a secret that no one should ever know about: he's actually Momo Kasuka, an up and coming female model! While shooting a new drama, he meets another arising newcomer named Yui Hazuki, and things are going to get heated!

A young man comes to Tokyo to become a poet (he actually composes a lot through the book!). But one can not support himself with poetry, so the hero works for a half-legal firm running all possible errands. In the process he meets a lot of people, both men and women, who are strangely interested not in his rhymes, but in his ...body! Absolutely lovely tragicomedy.
~by DaRyu

Aida Rendou, ex-student and would-be poet, struggles to earn a living in the big city. As a talent scout for the adult video firm, M+ Productions, he hunts for potential actresses but it's not enough to pay the rent. So boss Nanazuka offers him extra cash to use his body to seduce men and women alike. Michiru, a spoilt young woman with Yakuza connections, comes up with what appears to be a perfect solution: she'll be Rendou's patron in return for him working as her full-time host. Will Rendou finally be able to write his poetry? Or will he end up corrupted by the amoral dog-eat-dog world around him?
~by Lyrebird (Half-Baked)

Chapter 1-2: Suki♥Doki Tomita Emi falls in love with a player. How can she cope with him having so many girls? Chapter 3: Koibana - The Ex-boyfriend (story by YOSHI) Maho has an ex-boyfriend she just can't forget about. After being dumped, Maho started drinking and constantly sleeping only with men who ride motorcycles and look remotely similar to her ex, hurting herself in the end. Can Shunsuke, her best guy friend, help her out of this habit? (Baka-Updates Manga)

From ShoujoMagic:

People have gone so far as to call Kaname-kun a "sex machine" and "a man who exists solely for obscenity and sin." But now he's fallen in love for the first time with the super cool beauty Yumi-sama. Even when his only reward is her cold gaze, he persists in his desire to win her love--but he's struggling and suffering because his wooing technique gets incredibly clumsy when he actually cares about the result!

From Girls' Generation Scanlations:

High-school student Subaru wouldn’t reject a sexual favor, but dating is out of the question when he’s not in love. Stumbling upon a beautiful painting in school, he knows he’s found his first love – the artist behind the work. But winning the heart of his love interest isn’t going to be easy, particularly with his promiscuous lifestyle…

1. Teirui Makura
Popular honor student little brother, Yuua, and his kind older brother, Seigo. One step ahead in the puberty department, Seigo tries to put a little distance between him and his cute little brother. However, the innocent little brother is to blame with his defenseless skinship. Finally, Seigo's lust consumes him and he can't endure anymore. Once Yuua accepted that idea, his desire to be attached to his brother grew stronger every day.

2-3. Finger Biting, The Moon's Colorful Person

4. Choroize! Jigoku
A constant failure at job interviews thanks to his scary expression, Danda's employment agent sends him on a rather unusual assignment.

5. Loup-Garou Gokou extra
A short extra to Loup-Garou Gokou, chapter 9 in Hide and Seek.

6. Natsu ni Shini Yuku Monogatari (Dangerous Symphony)
Rock and Homero live in a world, where all kinds of laws restrict people and you can get arrested for the simplest things. Naturally, being love with another man is frowned upon.

1. Shatei Hani (Riflescope)
Having been noticed stealing, Hiiro cannot lose his chasers in the open streets. A strange man his age hides Hiiro by kissing him. The following day at school, Hiiro learns that the boy is a new transfer student to his class named Hasegawa Shizuga. Having stolen Hiiro's first kiss, Hiiro tries everything he can to embarrass Shizuga, before finally resorting to 'other means' in hopes of showing his dominance.

2. Pleasure Zone

3. Toriko
Onoda Kouichi sees honor student Atou in a bookshop accused of shoplifting. The next morning, Atou claims it was a misunderstanding. But, as Onoda points out, even a small misunderstanding will hurt Atou's reputation in school. In return for keeping this secret, Onoda says Atou has to become his slave....

4. The Chigiri (Promise)

5. Agreement

6. Zettai Genshu!
(Also included in Love Drug)
As Morimura Makoto grows more forgetful, his partner Tatsuaki devices a plan to help his problem. Until Makoto can prove that he has learned his lesson and begins to become more organized, Tatsuaki will with hold sex!

After being dumped by his girlfriend, Iijima (a tutor) is confessed to by his shy student Daisuke. The incident takes Iijima by surprise... and it also makes him realize that he's gay. But the 5-year age difference and his position as Daisuke's tutor makes Iijima reluctant to accept Daisuke's confession. However, Daisuke doesn't care about their differences and, despite his shyness, is determined to win Iijima over.

What happens when wolf (male top) meets wolf (male top), and both want to do the other?

From Blissful Sin:

Twins Keiji and Keiichi are both skilled in martials arts despite their innocent-looking faces. But the younger brother, Keiji, has harbored unrequited feelings for his older twin. What will happen to these feelings when Keiji suddenly enters a one-sided relationship with a schoolmate? What will happen when Keiichi also finds himself a lover?

A sexual omnibus full of trials and tribulations in these blue summer love stories.

This is the story of a boy who one day walks into some strange wood and is saved by a nymphomaniac godess who can not only take over his body (turning it into hers in the process) but can also transform him into a girl.

Kodaka Natsui, a naturally beautiful young boy, and a drop-dead gorgeous rich kid named Ritsu Yasaka both work as models.
One day, their agency requires both boys to attend an overnight retreat. Kodaka decides he wants to become a man worthy of Ritsu, so he begins to undergo training under Ritsu's valet...in more salacious ways than one! When he finds out what's going on, Ritsu can no longer suppress his overwhelming desire.

Side stories in volume 2:

• Waru Amai Mitsu
A police officer is attacked by a pervert in the middle of his very important assignment guarding the high-school student son of a politician.

• Urimasu!
Tsubasa doesn't like studying and can't hold down a job, but he still wants to wear cool clothes and live in a designer apartment. So, to accomplish that he decides to sell himself to men for "one night only". And he wont go "all the way" with them either!

Note: The overall story is unfinished because the mangaka passed away.

From Attractive Fascinante:

Takamura Hikaru is a handsome prince. However, contrary to the rumours and his cool appearance, he’s weak, a crybaby and likes snacks and sweet things. He kissed his classmate, Sugimoto Yuu, suddenly and Yuu thought it was just a prank. Yuu took a liking to the prince, but is the prince serious about it? Will their hearts be finally connected?

"Is this what sex is?!"

An English nobleman, Earl Christopher (33 years old), lives a systematic and routine life. Due to his methodical way of life, he has been isolated from the living world and does not even know what sex is...
One morning, Christopher comes upon a man camping in his territory. Because of Kanamori, a Japanese gardener, part of his territory has been unexpectedly turned into a Japanese garden with a water fountain!
Kanamori expresses his liking to the enraged Christopher and suddenly pushes him down...

A nobleman's first time and a barbaric Japanese man in a field of grass!

This manga contains a series of one-shots that feature Hanai Shishimaru, the perverted boss of ‘The Help-for-Help-Seekers Room’, which will do anything for their clients except murder. Causing divorces, turning someone gay, ‘relieving stress’ on a crowded train…… Just how far will he go?

The first, fourth and fifth one-shots, XI -Extreme Love-, Fool and Shadow Game, as well as the extra, La décadanse, are sequels to Buddy System.

Yuniko Sakuraba isn't your ordinary 15 year old girl. She is a die hard fan of the late actor Akira Nanae and she became a thief in an effort to recover and collect Akira's stolen memorabilias. She then encounters, the 17 year old actor Ryu Eba who has been labeled as the 'New Nanae'. She tries to steal his award which formerly belonged to Akira but is discovered. On the other hand, Ryu seems taken by the unique girl and offers to give her the award if she can steal it again. On the other hand, mystery surrounds Yuniko's past as she finds out that her mother, a former actress and who she hasn't seen because of her mother's illness has actually an amnesia and Akira's death has something to do with it! The story follows fun and hilarious adventures Yuniko and Ryu make as they steal Akira's other memorabilias in an effort to jog the memory of Yuniko's mother. Romance develops, secrets are uncovered and mayhem ensues. They will find that being famous isn't easy, jealousy is a trouble maker and staying in love and together takes effort.

Cute oneshot about a little boy who decides to wake up his older friend who lies in bed with a flu, and discovers that their bodies aren't the same.

Kento forces Jun into wearing a gakuran and seems to have some gakuran-fetish...