Love's Whirlpool (2014)

People gather at a split-level flat on a backstreet of Roppongi, Tokyo, men pay ¥20,000, women ¥1,000 and couples ¥5,000 apiece to spend the hours of midnight to 5 a.m. at a sex party. A moody Neet guy empties out his bank account for this night of pleasure, and a bespectacled college student who at first impresses as mousy and shy join the party. Presiding over this orgy are a jaded manager and bartender who explain and enforce three simple rules: Take showers prior to sex, use protection and respect the wishes of the women. Most dangerously, the Neet guy is falling quietly and hard for the student, who reveals herself as the horniest of all, while never quite breaking out of her shell.