Cristoforo Stati's effete "Orpheus" (early 1600s) is in the Mannerist style. His penis is still small, after the classical fashion.
Metropolitan Museum of Art, New York

200 years later, Bertel Thorvalden's Adonis I (1808-38) is still Mannerist. His translucent penis has a pinhole preputial sphincter, not necessarily a problem in real men.
Neue Pinakotek, Munich

This sketch by Auguste Rodin (1840-1917) is completely unselfconscious: neither Rodin nor his model would have given a second thought to the fact that the man still had his foreskin. It was simply a given.
Musée Rodin, Paris