how's your father

[lee howells]

i've heard sex referred to as 'a bit of how's your father' why?

[Quizmonster]

Just as a matter of interest, the phrase 'the other' is used in exactly the same way to refer to sex. This one can be traced exactly, as it was a creation of James Joyce's in his novel 'Ulysses', published in 1922. He used it in precisely the same euphemistic way, as described by Tartanwizard, in reference to 'how's your father'.