Either: unalias "nipple rings" or alias "nipple ring"

nipple rings is currently aliased to nipple piercing

nipple ring has over 300 images tagged

Either:
Unalias nipple rings from nipple piercing and merge it with nipple ring and have it imply nipple piercing,
or alias nipple ring to nipple piercing

considering the other aliases already in place for nipple piercing, aliasing nipple ring would be consistent. it’s also the more efficient of the two suggested methods, so it’s a win/win

Done.