A woman tries to give a man oral sex in a movie theater. No nudity. You just see her get on her knees in front of him and you see his face during.
A woman masturbates in bed. No nudity, but you see her hand over her breast and you hear her moan.
A man and a woman attempt to have sex. No nudity. In fact, there is no nudity at all in the film; every time someone has sex they are wearing either pajamas or a nightgown.
A lot of sexual dialog, jokes, and references.
It should be noted that these scenes take place between a long-married husband and wife and do not portray promiscuity, infidelity, or casual sex.