Shoujyo (2001)

Shoujyo (2001) follows Tomokawa, a rugged renegade turned restless cop who spends much of his time seducing lonely housewives and taking care of a mentally challenged teenager, Sukemasa. During a ritual night of drinking, he is approached by a 15-year-old named Yoko who offers sex for money. He turns her down, but their paths cross again. Yoko, it turns out, is Sukemasa's sister; and both are the children of his old flame Yukie. Tomokawa soon takes both teens under his wing, protecting them from their compassionless mother and lecherous stepfather. Akira Shoji shows off his bulge while bare chested and sporting tight white shorts. But Eiji Okuda takes the cake, showing off his butt, chest, and and even a flash of his sack in three separate scenes. His tight tush gets the most screen time, with a lot of bending and squatting to boot. Just don't be opposed to full body tattoos or you'll have to look elsewhere!