Sonja (Signe Egholm Olsen) is topless for an entire scene. She is wearing a bikini bottom. The scene lasts around two minutes; at times her breasts are hidden. The nudity is non-sexual, Emily Hirsch's character is taken somewhat aback by it (especially when she leans in and hugs him). Sonja kisses another character once or twice during the scene.
There is no actual sexual content in the movie, there are two scenes with nudity (breast), but it is displayed in a non-sexual way and is not focused upon.
Brief glimpses of breasts.
Chris (Emile Hirsch) is seen floating in a river while fully nude and his penis and pubic hair can be seen. It is a somewhat distant scene. At 1'26".
Two men drive by a nudist camp, where several people are seen completely naked. Brief and not graphic.
Tracy is sitting on a bed only in her undershirt and says to the main character that her parents are not home - implying the intent of sex, but he declines because of her age.