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.

All of the girls at his college love Suou Tsukasa and come up to talk to him on a daily basis. Unfortunately for them, Tsukasa hates girls that are straightforward like that, but is too nice of a guy to tell them that.

In fact, he has a crush on Kizaki Megumu, his classmate and one of the shy and least talkative girls. The professor in one of the classes they have together is Dr. Hime, a young teacher whose childish looks and short height makes her a target for her students to jokingly tease and treat her more like their friend rather than a professor.

After taking home the drunk Dr. Hime, who was served lots of alcohol by her students, Tsukasa learns a giant secret about her love life.

From Essence of Purity:

Takuma Ban, only son of the Ban familly from Hokkaido, comes to Tokyo on a quest: to find a fitting wife... with the help of Meari his cow. Jumping over a school fence while carrying Meari on his back, he unexpectedly meets a girl, Yuki Samejima. After one minute, he decides that SHE'll be his bride. Unfortunately for Takuma, Yuki's older brother, Ranmaru Samejima, is completely opposed to this.

Of course, the fact that Meari seems to have developed an instant "animal" attraction to him only reinforces Ranmaru's dislike of Takuma. Takuma is determined to make Yuki his bride and that, despite Ranmaru's stern "objections". Nevertheless, when not only Kei Enjouji but also Takuma's own family start getting involved, things get a little … "chaotic".

(Note: was originally debuted as a shounen manga, but Kodaka switched publishers and began writing it as BL)

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)

From Attractive Fascinante: Sensei rejected Fuji when Fuji confessed to him on graduation day. After that, Fuji always visited sensei and they still went out together. Sensei realized his feelings gradually and hoped to start afresh with Fuji. However, Fuji couldn’t believe it. But when Sensei’s ex-lover, Namiki, came back and wanted to reconcile with Sensei, both Sensei and Fuji found that they could no longer hide their own feelings anymore.

1-2) Sensei to Himitsu
Kaji's woken up from his nap hearing popular Tsunoda-sensei getting hot and heavy with another guy! But it's his partner, the plain Aritou-sensei that Kaji can't stop thinking about. Kaji's eyes are being opened as he finds that the needs and dark desires that can bind together lovers aren't always about love...

3-6) Hold me for all of Time
A researcher, Sawatari Kaoru, runs off after finding out that there will be no more funding for his research. As he wanders around he sees an abandoned warehouse where he could use to continue his research with his remaining savings. As he walks inside the building, he meets an arrogant little boy. Surprise ensues as to the boys identity, and the unexpected result of his own research...

Extra) And then...
Continuation of ch.1-2, a little into their future.

On the once-peaceful planet of Industria, constant battles have been fought over control of the planet. Astro is a dim witted but kind boy who tirelessly works to feed his "family," a group of orphaned children. One day, after being fired from his most recent job, the prince of Industria, Bulge, appears in front of him. And even more shocking, Prince Bulge looks and sounds exactly like Astro! One thing leads to another, and Astro now has to take Bulge's place as the heir to the throne of Industria! Suddenly, he's faced with the task of bringing peace and harmony back to this war-torn planet!

- Red Hawk NEO

Compilation of short stories:

1) 1000 Years, I Love
Hakua is sent into the mountains by the village to kill a ferocious tiger that has been attacking villages. The tiger, mistaking him for a girl, drags Hakua into the mountains to become his mate. Love soon blossoms as Hakua must teach this half human creature the meanings of his new found emotions.

2) 1000 Years, I Love Extra
Their love going strong, Hakua decides to go back to the village. Naturally Youko tags along and runs into some trouble in the human world.

3) Lying Words Honest Kiss
A slave merchant Kouhaku steals a beautiful boy Enji to sell him to a public house. Little did he know that the boy wouldn’t mind at all.

4) Fallen Warrior
A doctor’s apprentice Suiki finds a wounded samurai in the forest and takes him to his home to treat. The samurai Genka is really bad-tempered and the boy has bad history with samurai.

5) The Flower of Love
Story about an artist Sekka and a beautiful boy Joka he saves who later comes to serve as his model.

6) The Path of Pure Love

[From Beautiful Soup]:

"Self Portrait" is the story of a boy dating a yaoi fangirl who puts him up in a bet with an older, homosexual photographer (And he obviously loses). Hilarity and shounen-ai ensue.

DMG via Renta!

A story about the Sexual Harassment Punisher, Sakakibara, and his assistants - how they ‘punish’ those around them. Some comedy and BSDM themes, plus drama and action.

As a transfer student to a rough, run-down school populated by delinquents, Shindou tries his best to make friends. When he meets the ill-mannered Yousuke, heartbeats and tempers start to fly! It seems Yousuke is a "tsundere"--his gruff exterior hides a shy, sensitive side--and Shindou immediately finds himself dizzy over his combative new crush. Can Yousuke accept a relationship that goes against his tough-guy image? Or will his tendency to lash out at everyone around him drive even the earnest Shindou away for good?

From Viz:
Hime Kino's dream is to one day perform voice acting like her hero, Sakura Aoyama, from the Lovely Blazer anime. So getting accepted to the prestigious Hiragi Academy's voice actor department is the first step in the right direction! But on her first day of class she meets Sakura's grouchy son, Senri, who tells Hime that her voice is awful and Lovely Blazers is stupid. Hime will not let that stand unchallenged. She'll show everyone that she IS a voice-acting princess, whether they like it or not!!

Nagisa and her beautiful, intelligent best friend Yumi couldn’t be more different. Of course, her childhood friend, Ryou, is always happy to point this out whenever he can. When Yumi gets a crush on the equally intelligent and handsome Kei, Nagisa is determined to get the two of them together like any good best friend would, but it seems that Kei likes Nagisa’s outgoing personality more than Yumi’s shy one. And where does Ryou’s crush on Nagisa–and the one she may have on him–fit into all of this?

Shiina Momose doesn't believe in fortune telling and the occult, but for some reason, she can destroy anything with a touch. One day while on her way to school, a young man approaches her and claims to be a God. Furthermore, he believes that he was guided towards her and for that reason he has become convinced that she should become his first follower! Naturally, Momose refuses; but when strange things began to happen... she can not do something about it!

As a descendent of the famous exorcist, Abe no Seimei, Yuuichirou has always been able to see ghosts. Yuuichirou, as a child, was proud to be a son of the Seimei Shrine and wanted to follow in his father's shoes and become an exorcist until he's bullied by Ishida in elementary school. Now, as a teenager, Yuuichirou has lost his faith in Seimei. Can a visit from Abe no Seimei, himself, restore Yuuichirou's faith and close the rift between father and son?

Talentless, shy Tsubasa has just been accepted into the prestigious Seiko Academy. He soon gets mixed up with the most popular kids in school -- and the entertainment world! Forced to join the pop idol group RINX as their lead FEMALE singer, Tsubasa soon finds himself stuck in the middle of a cross-dressing comedy full of mistaken identities, blackmail, and kidnapping!

The Mana Tree, the giver of mana and life for the world of Fa'Diel, burned down nine centuries ago. A war erupted between faeries, humans, and others seeking the scarce power of mana that was left. When the war concluded, the drained Mana Tree slept and throughout the many lands of the world mana was stored in ancient artifacts.

Toto, and his pet Rabbi, have set out on an adventure to restore the world, and its mana, to its former self.

The Lands of Fa'Diel are populated with a large number of different creatures, including humans, faeries, demons, the jewel-hearted Jumi race, plant-like Sproutlings and Flowerlings, miner bears called Dudbears, and shadowy beings of the Underworld known as Shadoles. Fa'Diel is also the home of a host of anthropomorphic animals and objects, as well as monsters such as Rabites, Chobin Hoods, and Goblins.

Adaption of the PlayStation game of the same name.

Oneshot from Dekiru Otoko ga Suki Nanda! Jiyunja’s relationship with his teacher had been going on smoothly. There was only one unpleasant thing, Kizaki always said no to his intention to stay over, more less living together. Jiyunja felt confused, because Kizaki had said that he was serious about him. What infuriated him more was how smooth Kizaki always managed to avoid the question ‘why’, either by sweet-talking him, or drag him into love-making. One day, Jiyunja realized the amount of different kinds of shampoos in Kizaki’s bathroom, and suspected him for cheating on him with various women. Again, Kizaki tried to avoid the question and lure him into sex, but this time, Jiyunja felt too upset and ran away. Finally, the older man gave up and complied to his request, saying that Jiyunja would find out in the morning about the reason why he had been refusing to spend the night together.

From Tokyopop:

Fifteen years ago, a set of twins--a girl and a boy--was born to the king of Linevan. Shortly after their birth, a prophecy foretold that when the girl turned 16, she would bring about the end of humanity. To avoid this terrible fate, the king ordered the princess disposed of...scrapped!
She miraculously survived and was raised away from the kingdom that would kill her. But now she has turned 15, and the king's guards have caught wind that she's still alive...and they set out to finish the job!

Tachibana doesn't have it easy. His lover, Sawada, just doesn't care who sees them kissing! Tachibana doesn't want people judging them, while Sawada just wants to show his love when he feels it. Will everyone find out what kind of love they have?