Implicating blue_nipples → nipples
Link to implication

Reason:

This is rather obvious, no?
Only black_nipples are currently implicated, the other common colors should be too..

Ehh. Should we really have specific nipple colourations? Or are they for when they are so far out of the norm for their skin colour that it's something exceptional to tag?

As far as color tags go, those are among the most widely tagged. So I suppose some folks find them useful enough.

Color tags could use some pruning, but I don't think these popular ones are the best place to start. We have over 150 blue_* tags that are tagged less than ten times..