Green’s Dictionary of Slang

bog n.2

[? SE Bulgarian]

1. (Aus.) a racist term aimed at any non-Anglo-Saxon individual; also attrib.

[Aus] (ref. to 1960s) B. Hornadge Aus. Slanguage (1989) 171: He publically expressed the view that all foreigners [...] were wogs, dogs, bogs or logs.
[Aus]N. Keesing Lily on the Dustbin 182: Australian general slang employs a battery of racist phrases such as ‘wog’, ‘bog’, ‘Itie’ and ‘chow’.
[Aus]C. Bowles G’DAY 32: The bogs also have gang bangs in the backs of the bog wagons and the last one in stirs the porridge.
[Aus]D. Whish-Wilson Zero at the Bone [ebook] [T]he skinheads held the prime real estate of the Mall, the Bogs had lower Wellington Street and the Blacks still had large parts of East Perth.
[Aus]D. Whish-Wilson Old Scores [ebook] [T]here were no blackfellas or bog hoons or poor old immigrants on this street. It was all graphic designers and politicians’ offices.

2. see bogan n.

In compounds

bog wagon (n.)

(Aus) . a panel van or 4WD van, the back of which, with sound system and a mattress, is used for sexual encounters.

[Aus]C. Bowles G’DAY 1: She comes across for some of Shane’s mates in the back of their bog wagons.
[Aus]J.T. Pickle Aus.-Amer. Dict. 38: BOG WAGON: Not a septic tank pump truck but a panel van conversion fixed up with all the accouterments [sic] for scoring sexually.
[Aus]Aus. Motorcycle News 19 23/3: The first I saw was the brake light silhouette the rear of the bike when the bog wagon cut him off and made him brake.