At the beginning of the movie, we see some naked extras.

29 minutes in the movie, Matt Bomer is at a gay sauna, and we get a very brief view at his butt.

31 minutes in the movie, there is a very hot and long gay love scene with Matt Bomer. We get a very good view at his nice white butt.

20 minutes in the movie, Jonathan Groff undresses in front of the camera. Although the scene is hot, we see his hot abs, but no full nudity at that time.
Just a minute later, 21 minutes in the movie, Jonathan Groff walks bare naked in front of the camera for a full 30 seconds. His cut dick and balls are bouncing around. This is an amazing movie scene. Now we all know what Zachary Quinto wakes up next to.
83 minutes in the movie, Jonathan Groff gets naked again with another woman. We don't see as much. We see Jonathan Groff's butt but his penis and balls are kept in the woman's hand in that scene.