I've thought about trying this, but using super-glue to attach a small magnet to a fingernail instead - it wouldn't last as long (couple of weeks maybe), but it should be easier to feel the vibrations, as opposed to a ring.
Maybe. However, if you are feeling vibrations, that means you are in an oscillating magnetic field. I'd bet that you could feel the ring buzz. Touching my fingernail, and touching the skin where my ring goes, I think I might sense more easily with a ring. A tongue post is another option. :) Found this on Wikipedia: Cheap! I think I am going to get one and test it out:Neodymium metal dust is a combustion and explosion hazard. Neodymium compounds, as with all rare earth metals, are of low to moderate toxicity; however its toxicity has not been thoroughly investigated. Neodymium dust and salts are very irritating to the eyes and mucous membranes, and moderately irritating to skin. Breathing the dust can cause lung embolisms, and accumulated exposure damages the liver. Neodymium also acts as an anticoagulant, especially when given intravenously.[7]
Neodymium magnets have been tested for medical uses such as magnetic braces and bone repair, but biocompatibility issues have prevented widespread application.
I believe the movement of your own body is enough - the magnetic field itself need not be oscillating, to be detected (although an oscillating magnetic field would induce a lot more motion in the magnet). But I'm just speculating, have not tried anything yet.