I feel like this tag is not used nearly enough. There are plenty of posts with obvious nipple stimulation that just never gets tagged. There should also be a distinction between male and female, something like: "nipple_stimulation(Female)" - female nipple, and "nipple_stimulation(male)" - male nipples. Straight male nipple enjoyers are out there and a proper tagging system would really benefit them.
agree with @jonkler
@Darth Vader @ykk12138
feel free to propose a focus tag. every non-meta tag (focus, low, only, no, etc) that i can think of has historically been used even for the most minor & brief depictions of the tag in the gallery. wholeheartedly disagree with changing the rules now
@bajoujou the why is not relevant for the definition, the tag is for nipple stimulation by touching or making contact with them as in the provided description.
Does it have to be stimulation for the sake of stimulation? For example is there a difference between a guy playing with nipples because he likes nipples vs. playing with nipples for the specific purpose of stimulating the girl