A man has a winkle and a woman has a tuppence.

Fanny wiped her tuppence with a dish rag. Tally Ho.

-- so if you had to go #2, you needed to 'spend tuppence'.

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.

Gwenny, don't forget to wipe your tuppence!