The idea is it's a game like Tony Hawk, but for porn...you play as different porn stars, each with their own skill set and special moves, and you try to do the hottest scene, as measured using a point system, or accomplish some other goal (n times in each orifice, collect five bottles of champagne, &c.) within a limited amount of time. You get extra points for complex "combo" moves, varying positions, that sort of thing. As you progress, you unlock new special moves, hidden rooms, "upgrades" (surgical enhancement? Tantric training?), and secret partners. Of course there is a "group play" mode, which one would expect would be a hit at parties.

I don't know what to call it...there's something to be said for the simplicity of Doin' It or similar, but Peter North's Pro Boner has a lot of appeal as well.