My parents did it just the one time.

Many years ago, a good friend was telling me about the time she and her brothers were moving their recently widowed mother from the house they grew up in to a condo. Two of my friend's's brothers were moving the mattresses their mother and father had had for years and as my friend took off the bedding, exposing lots of stains, one of her brothers said, "wow, look at all the brothers and sisters we could have had!".

( There isn't enough brain bleach in the world )