Chastity is sometimes defined as "keeping sex sacred"; don't screw people before you get married, and don't do the sex outside the marriage.
Oh, you and your spouse want to fuck like rabbits? Go ahead and do it! God totally approves 100%.
There's a
reason Catholics historically have large families.
(Side note: My mother was one of six, and her mother was one of eight; I am one of 17 grandchildren. I went to a family reunion for my maternal grandmother's side of the family and there were more than 100 people there.)
So yeah, to tell the terrible joke: Catholics do it with God's approval.