<<waiting for tsuwm at this point???>>

I had nothing to contribute to this thread, but here's the obligatory pastes from OED, fwiw at this late date:

borak - Austral. and N.Z. slang. [Aboriginal Australian. Cf. barrack v.2]

Nonsense, humbug; chaff, banter; esp. in to poke (the) borak, to make or poke fun.

1845 T. McCombie Arabin 273 Borack, gammon, nonsense. 1882 Bulletin (Sydney) 9 Sept. 9 A smart fellow was ‘poking borak’ at them, and asked, ‘Is the snow in Japan the same as it is in Tasmania?’ 1898 in M. Davitt Life & Progr. Australasia xxxv. 192 A jest is ‘poking borac’. 1904 Blackw. Mag. June 832/1 One of the crowd was poking borak and said something pretty bad to him at the beginning. 1916 J. B. Cooper Coo-oo-ee ix. 113 At the same time he wondered whether Nipper was not ‘pokin' borak’ at him. 1944 J. H. Fullarton Troop Target iv. 34 You wouldn't be poking the borax, would you?

borax - var. borak. {they don't connect this with the other borax at all}

barrack - v.2 {a separate entry from the military barrack}
[app. orig. Australian (? alteration of borak), but E.D.D. cites barrack ‘to brag, to be boastful of one's fighting powers’, barracker ‘a braggart’, and barracking ‘bragging, boastfulness’ from northern Ireland.]
intr. To shout jocular or derisive remarks or words of advice as partisans against a person, esp. a person, or side collectively, engaged in a contest. Also, with for, to support (a player, speaker, etc.) (esp. by shouting). (Said of a section of the crowd of spectators, orig. Australian.) Also transf. b. trans. To shout in this way at (a player, speaker, etc.). Hence "barracking vbl. n. and ppl. a.; also "barracker n., one who barracks.

joe (waiting for dogot) friday

N.B. - truth be told, I didn't expect to find this one in the OED; just goes to show....