The middle English word "cod" meant scr*tum. (I don't know if that's a bad word or not. They are so funny here about which words to edit out.)
I'm always involved with creating costumes for plays, and recently had to make a number of medieval costumes with tights and codpieces. The Director was insistent that the legs of the tights be of different colors, so my friend and I had to make tights with one red leg and one black leg, or one green and one yellow, etc. In order to do that, we had to cut up two pairs of tights to make one pair.
This meant that the codpieces had to be really functional and not just fake. So we spent a lot of time doing research on what codpieces looked like, how they were made, and how they fastened and fit. It was a very interesting experience, to say the least.
The guys in the play were all so funny about it. Some were very embarrassed about getting fitted. All this "fitting" usually caused some (ahem) problems to arise. So, my friend and I learned to shape the codpieces on the inside (and out) and make them big enough to cover any, um, contingencies that might come up, so to speak.
Back in the day, they were molded and filled with a stuffing of rags, cotton, wool or even wood shavings, and then covered with colorful or decorative cloth. In our case, the Director wanted them made of the same cloth and colors as the tights, only with the colors reversed, so that if the actors left leg was red, and his right leg was black, then the colors of the codpiece would be reversed, so that the left half of the codpiece would be black (instead of red), etc.
We had to create a mold, the inside of which was ba
The Director gave us a high marks for our work. And, we got a real education. LOL
It's a Middle English term. Your "cod" was your... uh... potato sack...
Actually it was made from fish, cod to be precise.