Adult PC Game: Magic Femdom v4.2 by Volbells Archive

John is a down on his luck virgin who one day finds himself teleported into a small village inside the world of magic girls. They look like humans but are superior physically, mentally, and of course, magically. They are almost universally dominant sexually. John is given the simple task of getting to know the girls and deciding on one of them to become her familiar, the beloved servant of a magic girl. Familiarship is put in place by having sex before "the altar" giving them both the ability to leave the otherwise inescapable village.