Vegemite , n. — Green’s Dictionary of Slang

Vegemite n.

[the Aus. brown yeast spread Vegemite, equivalent to UK Marmite]

used in the following combs. to represent the anus and thus homosexuality.

Vegemite driller (n.) (also driller for Vegemite)

(Aus./N.Z.) a male homosexual, taking the active role in anal intercourse.

2002		I-94Bar 3:11 🌐 Yep, when you hear a poof joke, you might bite your tongue in these politically correct days, but these guys bite their pillows. They’re mattress munchers – and proud of it. Turd burglars. Drillers for Vegemite.
2003		McGill Reed Dict. of N.Z. Sl. 223: vegemite driller Active male homosexual.

Vegemite valley (n.)

(Aus./N.Z.) the anus or rectum, in the context of (homosexual) anal intercourse.

2001

OnLine Dict. of Playground Sl. 🌐 Vegemite Valley (travelling up the ...) n. Anus/Rectum (usu. with homosexual connotations).

drill for Vegemite (v.)

(Aus.) to perform homosexual anal intercourse; thus to be a male homosexual.

1985		B. Humphries Traveller’s Tool 20: Don’t run away with the idea that every Australian you meet likes drilling for vegemite.
1999		G. Seal Lingo 115: Related usages are to ride the tan track; dirt-track rider; ride the chocolate canyon, and to drill for vegemite.