The game with such a simple, yet expressive title is also rather simple and to-the-point in its concept: it is about having sex and nothing else. There is no real story in the game: in the beginning, a crazy-looking character named Mr. Funk, who speaks in Japanese with a heavy dose of stereotypical hip-hop lingo, announces that the player is now declared King of Sex and can therefore directly have sex with any of the three "available" young and pretty girls: Nana, the cute school girl, Makoto, the "mature" woman (probably in her early twenties), and the obligatory underage girl with pink hair, Ai.

The gameplay is dedicated entirely to sex, and features so many possibilities and precise commands, that Sex can be considered a simulation game. The goal is achieved with ease, since the player character has access to sexual activities right from the beginning. However, in order to see all the graphics, the player has to deplete every possible "activity tree", making choices between the player character's precise actions and ultimately changing the "course of the intercourse".

[From MobyGames]