This movie should be categorized as a R-rated due to the nudity and sensual scenes.
There are several kissing scenes between Norman & Frances. No nudity is shown above all scenes. Likewise there are no obvious sexual scenes among them.
The Woman & man kissing passionately while lean on the car. Both are fully clothed. But El wears a low-cut white tank top. Her cleavage is visible briefly.
Abbey wears a low-cut dress that expose the complete cleavage and a lot of skin around her breasts.
In one scene the couple is making out on the couch. The woman wraps her legs around him. fully clothed.
El is lying on the couch. She is fully nude. However no genitals shown. Ray sits beside her also presumably fully naked. However no genitals visible. sex is implied. This is very brief scene(5 seconds).
A man and a woman have sex on the bed evidently. We see the Ray's bare buttocks and a brief glimpse of El's bare breasts. But no other nudity is shown. He is shown thrusting vigorously and she moans loudly.