do you know what the 'F' word actually means? (apart from any modern meaning applied to it, which actually comes from its real meaning)
in the middle ages, as you may know, when a man wanted to have sexual intercourse with his bride, he needed the authorization of the king. So they would be put into a room with a sign on the door which said
<snipped> which means "fornicating under consent of the king", thereby, F***
That's why it is actually used as to describe a sexual act...