Green’s Dictionary of Slang

cat n.2

[Ital. cazzo, the penis/abbr. catso n. (2) or the perceived lecherousness of a SE tomcat]

[17C] the penis; esp. in phr. a bit for one’s cat.

In compounds

cat food (n.)

[1960s–70s] (US black) sexual intercourse.

In phrases

skin the cat (v.)

[19C+] to have sexual intercourse; thus cat-skinning n.