@MartinSleziak verbs in tags (in action mode) are usually in -ing: 'editing', 'flagging', 'searching', 'voting', 'cross-posting', 'voting', 'formatting' (I think there is no exception on meta-MO). For consistency I suggest to change it to "following-post', or 'following-a-post' (with "a" so as to avoid ambiguity with "next post").

On other metas, the tag names that I've seen are follow-post - stackexchange.com/filters/389862/follow-post and meta.stackexchange.com/questions/tagged/follow-post - and follow-posts - stackexchange.com/filters/389861/follow-posts and meta.stackoverflow.com/questions/tagged/follow-posts.

So to me this seems as a better name. I will not revert it if you change the name of tag - but I will not actively change it, since in my view this name has some (marginal) advantages.)

If you decide to change the name of the tag, it might be useful to create also tag-info with some basic information. My suggestions can be seen here: meta.mathoverflow.net/review/suggested-edits/1550 meta.mathoverflow.net/review/suggested-edits/1549