BoingBoing reader Drew says,
In his book "Law, Sex, and Christian Society in Medieval Europe," James Brundage creates a truly fantastic flow chart explaining when one can and (mostly) cannot engage in the physical act of love.Link.
At the time, a lot of Christian theology basically took the form of lists of things one wasn't allowed to do, so this flow chart probably isn't far off from the real decision making process prescribed by the church.
Previously on BoingBoing:
Reader comment: Pixel says,
I made an HTML version of the flowchart from that book several years ago, I hadn't been able to credit it at the time because I was given the flowchart as a Xerox from the book by a friend. Link.