Men, most of them naked, talk about their penises. They range from 17 to 70+, all from the U.S. The interviews are edited around themes: discovery, early sexual experiences, masturbation, size, oral sex, libido, performance, disease and maladies, maturity. A lexicographer discusses language, especially slang; a few archival educational-film clips divide the topics. Images and stories mix with facts and philosophical reflection. The usually private becomes public.