Maternity Monsters! ~Shinsou no Shinso to Ecchi de Abunai Shinsou Tsuikyuu!~

Monster girls have an almost impossible time becoming pregnant. Only about .2% of the time having sex can one get pregnant. For this end a special school has been created. Here humans and monster girls can attend school together where daily sex is required and open sex is encouraged.
After his marriage to Hakua and then to Ooko, Taichi lives every day now in lovey dovey baby making sex with his two wives. Eleonora Vletoblood, nicknamed Nora, an old acquaintance of Ooko transfers to the school. The two immediately glare at one another and Ooko does not wish to get along with the vampire girl. Meanwhile Nora is determined to make Ooko and Hakua's 'boyfriend' her own then throw him away like trash to prove her superiority to the wolf and rabbit girls.