Ryuuzaki is the athletic team's idol, but having been called a 'mermaid' by the swim team's Toya, he becomes determined to find out why. Watch as the story between these two individuals collides in this high school romance.
(Source: MangaFox)

From DMP:

Professor Asahina isn’t a very good teacher. Rumor has it that he spends his nights at love hotels with a different partner every night and he has been known to come to class drunk on occasion. When one of his students, Yuasa, finds a film of him having sex with an unknown lady in a love hotel, things get a little sticky. Yuasa promises to help Professor Asahina hunt down the tape and keep his secret safe, but for a price. Yuasa is known to associate with men and has had his eyes on Professor Asahina for a while.

Yaoi series of stories about life in a boy's dorm at a high school. The main couple in the first volume is Masamoto and Izuka, who are roommates. Masamoto saves Izuka from prostitution. There is also Hiroki who is sleeping with his teacher the dorm manager.
Vol. 1 Breakfast Club
Vol. 2 Room Mate
Vol. 3 Bed Time
Vol. 4 Pillow Talk
Vol. 5 Door to Door

Fresh-faced artist, Kojima Yoshimi, used to be the lover of the art gallery’s owner, Shibano. While diverting more of his attention upon his work, another man suddenly steps into the picture, and he apparently cares very deeply for Yoshimi… other than the titled story, “Yogoto no Tsuki,” this book also includes the expressive, heartfelt tales of young players; isolated, top-class businessmen; and the thin and fragile love between males.
(from B-U)

Set a couple of years after the ending of Breakfast Club:

Hiroki and Miki have settled down in their respective career paths—now a successful programmer and a researcher—when Hiroki suddenly decides that he wants to open a detective agency woth the help of Matsumoto and Iizuka. How will this self-proclaimed family business go?

The four Toura brothers have already succeeded in driving out all of the housekeepers that their father sent to look after them. But what will they make of Shinnosuke, their new live-in housekeeper... and a male one, at that?
(Source: Biblo Eros)