Green’s Dictionary of Slang

vengabus n.

[? ref. to Dutch band Vengaboys 1998 hit ‘We Like to Party (The Vengabus’]

(N.Z. prison) the urine testers’ van.

[NZ]D. Looser Boobslang [U. Canterbury D.Phil. thesis] 198/1: vengabus, the n. the van driven by the people who test inmates’ urine samples for evidence of drug use.