Sex as a power tool, human sexuality, romantic relationships (married or otherwise), and adultery are themed in all series. Occasional partial nudity, but not more than breasts, buttocks and flashes of implied sex acts.
Chapter 1 (S01E01): A man receives a call on the phone from his girlfriend and she tells him (in crass terms) that she wants him to perform oral sex on her. Later, the same couple is seen having sex in bed. We see his bare buttocks and her bare breasts, as. they get dressed he makes a comment about her licking his balls.
Chapter 2 (S01E02): Briefly, a topless woman is seen in a mans room while two men are doing drugs. Later in the episode, a woman (a prostitute) is told to receive money for taking it in her mouth.
Chapter 3 (S01E03): There is comedic reference on what a peach-shaped water tower resembles.
Chapter 4 (S01E04): The episode ends with a younger woman inviting an older married man to her apartment for sex, but nothing shown.
Chapter 5 (S01E05): An older man and a younger woman are seen in bed the morning after a night together. She disrobes but only showing bare buttocks cleavage (no nipples). She asks him to take "pictures I wouldn't want my dad to see", and lies back out of frame.
Chapter 6 (S01E06): A woman gives a man a hand-job under bed covers. He is resisting but she continues. for about 10-15 seconds.
Chapter 7 (S01E07): An older man performs oral sex on a younger woman while she speaks to her father on the phone - no nudity.
Chapter 9 (S01E09): An older man has sex with a younger woman, thrusting moaning, but no nudity is shown (both fully dressed).
Chapter 10 (S01E10): A woman is paid to seduce a political official. She brings him to his hotel room where ee see them passionately making out/grinding, but both wear their underwear. Also in the same episode, a married woman is stripped by her extra-marital lover but no nudity revealed.
Chapter 11 (S01E11): A woman strips to her underwear in a married mans bedroom. She puts on his wife's clothes and suggests they have sex in their wedding bed, but nothing happens.
Chapter 12 (S01E12):: Topless strippers are seen in the background of a scene. Later one stripper seen topless.
Chapter 14 (S02E01): A couple are seen having sex - thrusting and moaning but no nudity. As the woman steps into the shower, only her buttocks are glimpsed. Later in the episode, pictures of the woman naked are found and briefly (for roughly 1 second of screen time) in one photo seen topless and in various suggestive positions.
Chapter 16 (S02E03): Briefly, semi-pornographic images seen on a computer as the result of viral pop-up ads.
Chapter 18 (S02E05): Auto-erotic asphyxiation act between three people: a man bound tightly by rope and has a bag on his head while a woman performs oral sex on him. As another man goes down on him, the woman tears the bag from the first man's head as he climaxes. (Angles/objects obscure any view of sexual organs/contact)
Chapter 19 (S02E06):: Extremely briefly (blink and you'll miss it) a woman's nipple is seen in a topless photograph. Later in the episode, a woman grabs a man's crotch and asks, "Do you want to fuck me?". (Nothing happens though.)
Chapter 23 (S02E10): A man walks in on another man watching pornography, although he is fully clothed and is actually just literally watching it. The images seen on screen feature only woman in underwear.
Chapter 24 (S02E11): A lesbian couple are shown intimate in bed when a man spies through the window in bed making out. One woman sucks the others nipple while [implied] 'fingering' her. Also in the episode, a married couple engage a younger man in a three-way although all we see is the younger man kissing both the wife and husband.
Chapter 27 (S03E01): Briefly, a man's backside is seen as he climbs into the shower. Later in the episode, the same man buys a sex worker's services, she is seen naked from behind as she helps him out of his clothes.
Chapter 28 (S03E02): A woman climbs atop her husband and rides him - both fully clothed.
Chapter 31 (S03E05): Briefly an adult couple is seen having sex under bedsheets. There is no nudity, only thrusting and moaning.
Chapter 33 (S03E07): After a party a woman invites a man to stay, all we see is kissing, starting to take off their shirts, and in bed (covered) the morning after.
Chapter 35 (S03E09): The episode opens on a scene of a woman riding a man and moaning loudly. She comments that she did "cum"; the only nudity shown is the man's bare buttocks.
Chapter 38 (S03E12): A man and woman starts to kiss each and proceed to take each others' clothes off.
Chapter 39 (S03E13): A woman asks a man to "fuck her violently," the man starts to take off his pants but ends as the woman asks the man to look her in the eyes.
Chapter 40 (S04E01): A man is seen masturbating to a man telling him an erotic story in the first 2 minutes of the episode.
Chapter 41 (S04E02): A man and woman is seen kissing passionately but they stop when the woman tells the man of her tatoo removal. They soon continue again and the woman says "I want to taste you first", it proceeds with the sound of belt unbuckling and zoom into the man's face. It is cut immediately to next scene. No nudity is seen.
Chapter 42 (S04E03): A man is forced to pay by having sex... with another man. No nudity is seen. (Not a spoiler as it is for a sub-plot for only one episode.)
Chapter 46 (S04E07): Episode begins with bathroom sex between a couple, no nudity is visible. Scene occurs between 2:30 and 3:45.