Kimberly got naked in the last moment after partying with Stuart. Body showed from behind.
A man comes out of a bedroom wearing nothing but a towel. It is implied that he had just had sex with a girl who also walks out later. Stuart discusses them having sex briefly to the two of them.
Stuart talks about how sex always makes him hungry. And that masturbation does as well.
The entire show is about a lonely Englishman trying to find love in LA.
Kives sends a picture of his penis to Stuart. We see the picture, in detail for about 3 seconds. In a separate episode, a similar picture is sent to Stuart again.
Although actual intercourse is left to the imagination, characters talk about sex and trade occasionally crude sexual banter (like "I'd so like to come on those t-ts.").
A man and a woman go skinny dipping. We see her take off her dress from a distance. While in the water, she says "my nipples are so hard" We can barely see her as it is night but her buttocks is clearly shown. The man takes off his shirt and trousers, but changes his mind and puts them back on(we see nothing from the waist down of the man)
Lots of sexual references. Some stronger than others.
People spot a condom that is in Stuart's front pocket. Throughout that scene he is attempting to chat up a girl so it is implied that he wanted to sleep with her. In another scene, Stuart hides a condom in a drawer before a girl arrives. He presumes that he's going to have sex with her.
Some kissing.
Two men who were taking cocaine come out of a bathroom stall. When asked what they were doing, one of the men says that he was sucking his friend's penis. This is frequently mentioned after wards. There is also a crude drawing shown at the end of the episode showing a man sucking a man's penis. It's captioned with the word "C*ck"