There are a few brief shots of men's butts shown while they are showering in a prison (somewhat at a distance) within first few minutes of the movie.
Throughout the boxing tournament, there are various shots of ring girls in skimpy thong bikinis (mostly background or briefly walking past in foreground while the focus is mainly the boxers or trainers talking) however, still very visible in those shots.
A woman wears very short cutoff shorts and a man admires her in them
A man gets into a car with a woman, who's head disappears into his lap as he drives off. Fellatio is implied.
There is a glimpse at a dead man's buttocks.