Drugless Sex
Odd but super sexy. This takes place in a world where a infection is rampant. When people are attracted to an infected person the person emits a phermone in response that makes the attracted person lose control and frequently assault that person. There's a pill that's handed out to suppress the phermones. Ch1) An infected salaryman, Hinoki is nervous about the cafeteria worker, Sugino, being attracted to him, but it turns out Sugino is infected too and thinks that Hinoki is attracted to him. Basically they're both attracted to each other and both infected. Ch2) High school playboy takes advantage of his infected status by screwing anyone attracted to him, but he bites off more than he can chew when he realizes a gloomy otaku in his school is attracted to him. Ch3) Two scientists are both infected and screw each other, seke-style. Mura, the dark-haired one, infected them both on purpose so they could test each other. Ch4) Back to the 1st couple. Sugino doesn't like Hinoki changing medications so he give him a placebo and they both have sex with no suppressants.
Drugless Sex 2
This is a sequel and it follows the story of Tatsumi, who's infected with the pheromone syndrome (which makes people who are attracted to them lust after them uncontrollably), and Inui, an otaku who's in love with Tatsumi. Tatsumi is swept up by the persistent Inui and overwhelmed by their sex, not getting much opportunity to work out what his feelings really are. After they graduate they start living together, but Tatsumi starts feeling confused and insecure and, wondering if he can even have sex with women anymore takes a coworker home. Nothing happens but Inui is livid and they get into a fight.
Kurakura Inma
Naoto wakes up one morning with a tail and thinks he's dying. Then he gets rescued from molesters on the train by Miyuki, a guy he works with that never seemed to like him, and they end up banging in a train station bathroom. Naoto finds out from his sister that he's part incubus and now attracts men.
Bokura To Usagi No Koi Wa Sensou