Green’s Dictionary of Slang

gristle n.

also gris, grist
[SE gristle-bone, any part of the body consisting of gristle]

[early 17C+] the penis.

In compounds

gristle-gripper (n.)

1. [1980s] (Aus.) a masturbator.

2. [1990s+] the vagina.

gristle-hammer (n.)

[2000s] the penis.

In phrases

give someone the gristle (v.)

[2000s] (US black) of a man, to have sexual intercourse.