Sex is a key component throughout the series. Simulated coitus, and less often, fellatio and cunnilingus, occur regularly, showing motion but no nudity other than, on a few occasions, men's butts.
Breast size, large and small, drives many plot points. There are a couple of scenes of over-the clothes groping of breasts and male and female groins, and cleavage is a frequent focus of attention. Penis size gets somewhat less discussion. Sexual satisfaction, infidelity, and STDs are frequent topics of conversation. A lot of cheating and casual hooking up occurs.
Sexual language is prolific, explicit, and vulgar throughout.