What is Headmaster's Duty?
1.
The act of soliciting for the purposes of prostitution, i.e. a girl "working" in a bar, usually with unnecessarily revealing skirts and tops.
Has its origins in South London; etymology rumoured to be an oft-absent headteacher caught soliciting in the late 1970s. In order to avoid direct reference, the claim that he was doing his 'duty' evolved into 'headmaster's duty'.
I think she's probably up for a bit of headmaster's duty
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