You want clean?

A flea and a fly in a flue
were caught; didn't know what to do.
"Let us fly!" said the flea.
"Let us flee!" said the fly.
So they flew through a flaw in the flue.

or

There once was a lady, Simone de Beauvoir,
who committed a dreadful faux pas;
she loosened a stay
of her decollete
and exposed her je ne sais quois.

But I prefer

A pretty young lady from Exeter
had the young men all craning their necks at her
and some were so brave
as to take out and wave
the distinguishing marks of their sex at her.

Cheers, Rowan