Not very explicit for a film about escorts.
It's implied Chelsea has sex with a client(they embrace and kiss, with her pushing him onto a bed). When she wakes up, full-nudity is briefly visible, but not very easy to notice because it's a zoomed out, darkly lit shot. She mentions having sex with him for an hour in her diary.
Chelsea meets a client, and while you don't see anything(they talk). She later mentions that he told her to masturbate, and then masturbated to her doing that.
Chelsea kisses and embraces Chris, then they fall back onto a sofa(it cuts to the day after a couple seconds later).
One of Chelsea's clients is a jewish diamond salesman, and he takes her into the backroom. She's in a skimpy bra and panties(revealing bare butt and back), and he unbuckles his belt. They're standing up, but we don't know if they're embracing or actually having sex.
After the end credits, she's seen washing a client's hair while naked. Because the man is sitting in a bath-tub, full nudity is obscured, but breasts are visible.