Naughty Boys 2001

Gacchan lives with his lover Takayuki, but has a bad habit of sleeping around. It's Gacchan's birthday, and Takayuki is waiting at home to celebrate. Gacchan, however, has not only forgotten about his own birthday, but he's been out playing around. When Takayuki finds out, he's furious, and announces that he's going to cheat on Gacchan in turn.

In the bar district, Takayuki has gets into a series of dodgy situations with strange characters only to be saved when Gacchan, desperate to stop his boyfriend, secretly gets in the way.