Green’s Dictionary of Slang

royal n.2

also boss’s royal
[SE royal, i.e. their privileged position in the working hierarchy]

1. (N.Z.) a management stooge.

[NZ]N.Z. Observer (Auckland) 24 Nov. 7: Invariably the ‘royals’ receive preference. These watersiders are well known to the stevedores [DNZE].
J. Winchester (Wellington) postcard DNZE (1998) 684/2: boss’s royal is a waterfront term for a boss’s stooge or pet .

2. (US) to play host.

[US]Seattle Star (WA) 11 Nov. 8/3: ‘The gimp was doing the royal with some clover-kicker at the next board.’ [The boss was entertaining a friend from the country at the next table].