That's an easy one.
It happened what seems like hundred years ago... probably late 70's?
That's when EVERYONE had to swap wives...... I think it was a law back then.....

My best buddy & his wife swapped with me and my wife one night.
So he got to fuck my
luscious wife.
I got to fuck his double - fugley wife who was also lousy in bed.
I don't know what I was thinking....

I guess I just had the need for some strange pussy.
My buddy was the one who most wanted it, but all four of us felt the need to do it just to be cool.... since EVERYONE else was doing it. or so it seemed at the time.
.