how's your father

Etymology
. A popular catchphrase of the 1910s popularised by music-hall entertainer Harry Tate, who used it for comic effect to change the subject away from one about which his character was ignorant (hence sense 1) or a taboo subject (hence sense 2).

Noun

 * 1)  A whatsit; a thing which the speaker is unable or unwilling to specify more precisely.
 * 2)  Sexual intercourse.
 * 1)  Sexual intercourse.