From Impossibility:

High school student Hasumi Kei has only one goal in life--that is to visit her classmate Kanzaki Kyosuke's apartment! Seeing how the two do not know each other, Kyosuke refuses to allow her to be anywhere near his apartment... But Kei is relentless, demanding to get her way... but why?

1-2) Unspeakable Relationship ~ Inoue's Case
Kensuke meets, through a dating site, a certain "Michiru-san" who's erotic, has a sexy beauty mark near his mouth, and is great at playing coy. Although they both lie and claim they're 20, Kensuke is actually 17 and Michiru-san is actually 26. Not only are they 9 years apart in age, but Michiru also ends up being a teacher at Kensuke's school! As soon as the truth is out, Michiru stoically proposes to end the relationship.

3) Unspeakable Relationship ~ Yamada's Case
It seems Inoue's friend Yamada has his own forbidden love.

4) Not Cute

5) Under Hair Cut 100

1) My Elegant One When Tatsuya Koumura runs into Miyata because of his job, he's wary. Throughout college straight Miyata had protected Koumura from perverts, until Koumura's feelings became something he had to hide. But now that Miyata has found him again, he doesn't intend to let Koumura go that easily. 2-5) The president of Kyouei Group, Kyoujima Eiichi, is making others jealous with his successful career and passionate love life. His secretary, Togawa Akihiko, is an honest man and has been secretly in love with him. Includes a Las Vegas working trip that shocked the secretary with the president's past… 6) I Hate You the Most in the World Since his grandfather's death 17 year old Kazuki is alone in the world with only his guardians, businessman Kyoujima and lawyer Sasai to look out for him. Stung by Sasai's indifference, Kazuki finds himself leaning on Kyoujima. How will Sasai react? First series out of four. Sequel: "Suit o Kita Akuma"

From Attractive Fascinante: Will Eiki and Mairo finally be together? Or will Mairo get married for the sake of the family?

Hime Koibito is about two girls in an all girls boarding school (like so many other shoujo-ai) and an upcoming Christmas eve dance. Karen whose family owns a public bath is in the middle school and asks Nakayama an "outsider" and new student to the high school to go to the dance with her. Nakayama is bullied and shy, but Karen is outgoing and determined to get Nakayama to go to the dance with her....

This oneshot is also reprinted in Petit Peach (Puchimomo, ぷちモモ) published in 2006.

From Fantasyshrine:

Sakura Kazuki is a telepath who can sense negative emotions such as malice through contact. Despite his cute 17-year-old appearance, he’s in fact a 26-year-old rookie detective in the police force, Division One. Teamed with his seasoned, assertive partner/mentor, Shido-san, Sakura often works undercover. His disguises consist of a high school boy, an office lady, and he even gets to wear a cat suit!? Cosplay (costume play) in the police force!?

Rain Jewlitt, known as the Methuselah, is a spaced-out, immortal, 624-year-old man dressed in priest's clothes. He's got eternal youth and a large price on his head—put there by those questing after the secret of his immortality.

Machika Balfaltin is a tomboyish, energetic 14-year-old girl who, upon the death of her grandfather, sets out to kill Methuselah, the one bounty her assassin grandfather, Zol the Grim Reaper, couldn't kill. Instead, however, Machika ends up being saved by Rain again and again from other aspiring bounty hunters attacking them both.

Sound like the beginnings of an odd relationship? You won't believe where their journey takes them...

1) Explosive Fairy Tale
Childhood friends, Danzou and Shou, run into a dangerous bump in their relationship when Danzou reaches puberty ahead of his smaller friend and begins to see him in a whole new way.

2) Undoubtedly Useless a Painful Season

3) A philosopher in Love

4) Follow-up

5) Awakening Puberty

6) An Eyeful and a Handful
Not scanlated.

7) Going into Overtime
Not scanlated.

8) Afterword

For Tanpopo Yamazaki, life at the elitist academy in Tokyo seems way out of her league. The children of wealthy families snub her, other students make light of the fact that she actually tested into Meio, instead of relying on family connections, and the cute boy she saw tending a dandelion the day before wouldn't even acknowledge her existence. Hoping to make friends and have some fun, Tanpopo starts up a gardening committee, but will this help her survive in a school where superficiality and money reign supreme?

1-2) I Love You Too Much
Sweet story about Kouji's secret love for his friend's younger brother Mizuru. He is satisfied with any chance to spend time with Mizuru but one day, he suddenly realizes that his time with Mizuru will be coming to an end. Will he finally confess his love or will he let this love remain buried? Story also published in chapter 5 and 6 of Kagakushitsu e Douzo.

3) Cruel Love
Kiichi's parents died when he was a child. For the past ten years he's lived with his uncle whom he loves. Even though they have sex Akumitsu never tells Kiichi he loves him. Is Kiichi just a toy?

4) School Scandal
Uemura is the only one who treats his classmate Atsushi like a friend instead of star actor. But is friendship all Uemura feels?

5) Am I Your Dog?
Kei is considered a troublemaker at school, so when his sempai Kagami catches him smoking Kei has to do what he says, or risk getting expelled. But to be sempai's pet dog? And how is Kei's brother involved?

6) Our Future Diary
Eight page short about a perverted teacher and a gay porn video.

7) Love Facism
Rui is dating Yuka, a very pretty girl from his school. Then he meets exchange student Tooru. Tooru and Rui had a relationship in the past, but that's all over, right?

Japanese yakuza clan heir Ranmaru just got married on a lavish cruise ship, but things aren't as they seem. The marriage is just for the appearances, and he ends up getting drunk and spending the night not with his bride but with the sexy ship captain. When the two men meet again in Italy, it is the start of a spectacular love story.

Includes an extra story called Koi no Annainin (The Guide of Love).

From Nekohana:-
Meet Izumi and Tachibana. They're right in the middle of a very hot and heavy romance. Seems normal right? Except Tachibana is a teacher at Izumi's all girls high school. Calm and collected Izumi is part of the student council. Tachibana is lecherous and is always trying to find a way into Izumi's uniform. See if they can handle their hush-hush relationship and themselves.

1-4) Ikenai Otoko
Ryou was dumped because of his lousy sex techniques and in order to improve his skills, he turned to JS Pro, a company full of handsome men. His debut as a seme was a complete failure! He decided to challenge the uke role by teaming up with Tatsuya, a man he admired, however…

5) Take Love Easy
The first encounter of Shino and Josh!! "Shino ~ The person you saw in the video wasn’t the real me… Would you let me hold you and show you the real me?" "Josh ~ Is my roommate truly the actor in the gay video that I fell in love with!?"

6) Ikenai Invitation
The extra chapter features Iijima from Rumble Rush.

Collection of short stories:

Koi wa Tenka no Mawarimono

Ikenai Candy Love
Satoko has suddenly been informed by her irresponsible boss that she’ll be fired soon and only has one more month before she is kicked out. She tried to reason with the company's number two, Tanigawa-san for some leniency but the cool yet quiet Tanigawa just agreed with the boss. But on her way home from work, Satoko found Tanigawa in the midst of something naughty and he finally confesses that he’s a sex addict! Will Satoko now use Tanigawa's dark secret as leverage to keep her job? Or maybe she wants to be a part of the naughty deed herself!

Katekyoushi no Okotowari

Honey-Comb

Nagisa no Shy Boy

Shizukuishi has a problem. Well, a number of them, actually: She wets herself chronically. She occasionally loses complete control of her actions. She's being hunted by an army of robot maids. The root of all her troubles is the soul of the ancient destructive giant Daidara-bocchi, which is sealed in her womb.

But she's not alone. By chance, she became attached by a thread made of light to Kouki, a "contractee" who helps maintain the burden of the seal within her. Together, Shizukuishi and Kouki face her toubles and fight against the evil robot maids, but if they get too close to each other, then something terrible could happen...

Born of an Incubus clan, Tsukiya has had enough of the pain that comes from only bringing death to the human men he comes to love and so closes his heart, and denies himself from ever again feasting on human souls. Gento, the ever persistent demon that he is, has never been far from Tsukiya's side and has seen him mourn the death of many lovers, never understanding why Tsukiya continued to seek a love with these mortals that would forever bring him nothing but pain. Now years later can Gento, still ever pursuing Tsukiya, finally win over Tsukiya's heart for himself, and can Tsukiya help a young Incubus through the pain that comes from falling in love?

'S' is a known as a bully caretaker, who avenges her bullied clients -- for a price, of course.

However, in reality, 'S' is a nerd named Kang Song Ih, with a twin brother named Kang Ah Eul, whom she loves above anything. Ah Eul attends Chungha High School, a famous and expensive school, but over winter break, he attempts to commit suicide. Song Ih, determined to understand why her brother tried to kill himself, attends Chungha High School, pretending to be Ah Eul -- uncovering the reasons why Ah Eul was driven to suicide, including one mysteriously handsome but "bad" guy named Suh Ga Yoon.

Read as you follow her life while staying in an All-Boy's school and living in a dorm -- with a male roommate, who happens to be a famous singer and someone she as "S" had once nearly beat up.

Watch out! Whoever bothers "S"'s brother, prepare to face her!

Shy Ichitaka has a crush on his high school classmate Iori, but ever since she posed for semi-provocative swimsuit photos in a magazine, she's had a lot of sleazy guys hitting on her. Ichitaka's afraid to make his feelings known for fear Iori will think he's just another creep.

From Viz: Ion Tsuburagi chants the letters of her first name as a charm to bring good luck when she needs it. Then she meets Mikado Hourai, the president of the Psychic Powers Research Society at school, and touches a mysterious substance he's been developing. Now chanting "I-O-N" gives her telekinetic powers!