You didn't read the article I linked above?
Here:
Once you get yourself a quality quiver it will need to be broken in. The quiver should eventually conform to your back, the tube collapsing on itself. This holds the arrows still and securely. Several products can be used to help this conditioning. Montana Pitch Blend, mink oil, or even canola or olive oil can be used to soften and condition the leather. During the summer months put the quiver out on your deck or atop your car and let it heat up really well. It will readily take the oil or treatment in this way. It is also a good idea to retreat the quiver thoroughly once a year to help prevent dry rot and preserve the life of the device. On a new quiver I will fold the top down to meet the bottom and sit on it as I commute to work back and forth every day, some folks put it under their couch cushions but I try to stay away from the couch. Fold, bend, and re-treat until the quiver readily collapses flat under its own weight around your back.