At one point male_udder had a sizeable amount of posts and was used for masculine-bodied (male, andromorph, male_herm) characters with udders. No idea why it used singular udder rather than udders. A year ago, it was manually nuked for some reason, but it has sense been added again on 19 posts, and there's also 2 posts tagged male_udders.
I like this tag and would rather keep it (rename it, if appropriate). At the very least, can we agree not to manually nuke sizeable tags? Either it's valid and should be aliased to male_udders or another appropriate name, or it's invalid and should be changed to an invalid tag.