"Escape From Alcatraz" - Clint Eastwood, Bruce M. Fischer, et al (1979)

Any prison movie from the 70s, no matter what, is going to have nudity in it. While star Eastwood is shyer than his fellow showering buddies, we do get a quick peep at his little Clint (assuming that's not a stunt double)...

Clint Eastwood, Bruce M. Fischer, et al - Escape from Alcatraz (1979).mp4 | 55.6 mb