From Renta:

Kippei is a bum, flitting from one partner to another. When his girlfriend dumps him at a cafe, he notices the same thing happening with a male couple at the next table. Deciding to forget their misery together, Kippei and the average-looking dumpee, Sosuke, head to a hotel. Once there, Kippei is floored to see how aggressive Sosuke actually is. This is a heartrending, raunchy story about a playboy who's never known love and strait-laced doctor. The latter's unpredictable personality will make you faint!