There is a lot of nudity from the beginning to the end of the movie, full frontal and rear (genitalia seen from rear, also), men and women, though penises and testicles are much more present in the movie than vulvas. There's a scene of sodomy between men. There are scenes of totally or partially erect penises. With an exception, all actors show perfectly shaved bodies, genitalia included.
The main scene of erection (no prosthetic) occurs towards the middle of the movie. The man is caressing the woman's clothed crotch and when he stands; the woman puts a red ribbon on the erect penis. The scene lasts for many seconds and you can see all in every detail. Then they proceed to simulating intercourse (in different positions) totally naked.