Green’s Dictionary of Slang

gutstick n.

the penis.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1896		Farmer Vocabula Amatoria (1966) 35: Béquille du père Barnaba (la). The penis; ‘the gut-stick’.
1983		R. Klein Jailhouse Jargon and Street Sl. [unpub. ms.].
1999		Roger’s Profanisaurus 3 in Viz 98 Oct. 5: boh exclam. The noise made by a man after a particularly heavy woman has bounced up too far and sat down hard on his gut-stick, breaking it in two. Reportedly Prince Albert’s last word.

In phrases

have a bit of gutstick (v.)

of a woman, to have sexual intercourse.

1890–1904

Farmer & Henley Sl. and Its Analogues.