I'm serious. That was my mother's polite euphemism for it and as a child I thought that was the real word for it.
Term comes from the the first Femaile public toilets.
on the 11th February at 51 Bedford Street, Strand, London. These ‘Public Waiting Rooms’ contained water closets in wooden surrounds.
The charge was 2 pence entrance fee. and whilst still a semi taboo subject the term Tuppence was coined.
If anyone tries to touch your" tuppence" scream and run home as fast as you can.