Old term used to refer to adult
relations between a man and a woman. The birds reflect women, the bees reflect men, in a subtle but notable
reference to sex.
These days, we tend to be a lot more abrupt when discussing these issues pertaining to 'the birds and the bees'.
Why yes, son, she is a fine looking
young lady. One day, I must sit you down upon on my knee and teach you about
the birds and
the bees.