Green’s Dictionary of Slang

get off v.2

1. [20C+] to gain satisfaction.

2. [20C+] (orig. US) to achieve orgasm.

3. [1920s+] (US black) to achieve one’s object.

4. [1930s+] (US) to improvise or play music skilfully.

5. [1910s+] (US) to enjoy, to be stimulated by.

6. [1970s+] to bring one’s partner to orgasm.

7. [1990s+] to please or stimulate someone else.

8. [2000s] of a prostitute, to find a client.

In phrases

get off with (v.)

1. [late 19C+] to strike up a relationship with a potential sexual partner (short of actual seduction).

2. [1930s+] to seduce, and poss. have sexual intercourse with.

3. [1990s+] (UK teen) to indulge in a session of French kissing.