Green’s Dictionary of Slang

hot rocks n.1

[hot adj. + SE rocks/rocks n. (8)]

1. [1920s] (US campus) someone or something splendid.

2. [1930s] (US) biscuits.

3. [1940s+] (US) esp. of a man, strong sexual desire.

4. [1950s] (US) as a form of address, usu. ironically.