Lots of sexual humor and references throughout:
There are many talks about genitals, sex, sexual relationships etc.
There is a reference to a penis during intercourse.
Roz has a sex toy and mentions that it has a musical rhythm that gets faster the more they thrust.
Jack is shown with an erection.
There is a sex class with Ross that features scantly clad women.
Ross does a show on TV with many mature sexual subjects.
There are many more mature sexual subjects throughout the movie.
In one scene Greg is at a woman's house. Andie is drunk and tries to have sex with him, she strips down to her bra and underwear, no sex happens.