1962 N. Freeling i. 37 ‘I'll be Mum,’ he said, and poured the coffee.
1965 J. Potter xv. 147 I did the chores as mum..the tea-tray ploy was one of the standard fitness tests for prospective employees.
1992 M. J. Staples (BNC) 65 ‘Shall I be mum? Yes, I might as well.’ She poured the tea.