She’s been photographed doing something she shouldn’t have… Now she’s blackmailed into being a plaything for men.
Source: AniDB

There is a strange epidemic running rampant at the local inpatient hospital. For some reason every night the nurses are feeling an uncontrollable urge. They have no choice but to satisfy it with the patients, the doctors, and even each other. The new resident doctor has his own itch to scratch, as well as a suspicion that someone is behind this impromptu sex ring.

OVA produced by the manga publisher Toranoana.

Saori is cute, perky, and dreams of being a star! Along with the beautiful Yuna and the striking Erica, Saori is part of a new female pop group named Twinkle – and this hot little group is ready for their big debut!
But this tantalizing trio is about to discover that the music industry is ruthless and demanding of its female artists! First, band manager Masaki decides to give Yuna and Erica a special session in pleasure and pain… Then, as lead singer, it’s up to Saori to get the band past Kijima, the shady don of the entertainment business. Using his position to fulfill his wildest desires with all of the hot new pop idols, he’ll never even consider giving anyone a chance at a big break until after his carnal desires have been satisfied. Saori’s mother knows this all too well; to get Twinkle noticed, she’s already given in to his erotic demands.

Based on a game by Alice Soft.
Yamamoto Akuji noticed that the world is a totally different place after his release from prison. He experiences Osaka as something very new and strange after he got out of prison. During his imprisonment the hierarchal structure flipped upside down making it a world where women dominated over men.
Militia, churches, businesses and private businesses are operated by a female figure. Men were powerless, being controlled and enslaved by the women of Osaka. Being angered by the situation, Akuji and his partner Satsu begin their payback by teaching the stuck-up women in Osaka a little lesson…

Based on a game by Tanuki Soft.
Kazuma returns home after a long absence and becomes a part-time home tutor to his younger sister and a few other girls.

Based on a doujin game by Orcsoft.
Saiki Yasuo is a 45 years old office worker. After 20 years of marriage, his wife asked for a divorce and left him. Now, depressed, he spends the nights drinking alone, until one night a girl from the St. Marian Academy approaches him looking for a client.
(Source: English DLSite)

Takumi lives next to Mitsuki and Satsuki’s house. They have been good friends since they were kids, going shopping and skiing together. One day, Kazuyoshi, Takumi’s father, brings two girls, Saori and Yui, back to their house, and accepts them as new family members. At first, he is confused, but gradually becomes closer to them…