If you have an area on your finger that is tiny enough to let your ring simply sail around, that can be solved by adding small bumps on the inside. These are of the same metal as the band, and soldered to its interior, on the bottom shank. They keep any ring in perfect position after you wear it that way.
The usefulness of this is most obvious when you are wearing multiple rings as a stack on the same finger. With bumps added to the looser ones, you can rest assured that there will be no more spinning that leaves one of your plain or diamond-studded bands facing the wrong way.