But there are many kinds of "commitment" rings, from marriage to engagement to going steady to friendship rings... as well as rings of affiliation to schools, societies, fraternities and sororities...

So are there many levels of collaring... so long as both parties understand and agree to the meanings and the levels of such collarings... Not all need be worn around the neck. Bracelets or anklets can also represent the shackes or manacles of being bonded.