I suggest nuking the tag and replacing most of it with ass close-up, the rest is just ass. In the rare case that point-of-view applies, it can be tagged separately.
P.S.: You linked to point-of-view, but we don't have that tag. But we have pov, meaning first-person_pov. As in, the characters are interacting with the viewer. (in post #740724, Sanae is kissing me)
Also, technically, every image has a point of view, but I understand that a tag named "pov" or "point of view" might be used for notable ones, such as the first-person one. In an alternative universe, pov could be our substitute for foreshortening, or from below, or whatever.
That still does not explain how the tag should be applied. If it's just "emphases is placed on x", then the name "pov_*" was poorly chosen and we're back at X_focus tags. And body part tags are already focus tags.
I agree with S1eth. We should get rid of these pov_<body_part> tags.
For one they have nothing at all to do with point of view, so they're very badly named. Furthermore, pov_feet seems to be the same thing as just the feet tag itself, while pov_ass is just ass close-up as previously mentioned.
First of all, most of the posts under pov_feet are not close-ups. For example, post #1562371 - a foot is visible, but it's not a close-up. So close_up_feet would not be any more accurate a name than pov_feet.
Second, we already have a close-up tag. I don't think we need any subtags for it. Let's just get rid of them.
I'm for removing them, but the existing ones need to have the relevant tag added first. I added a few where ass was missing, but for feeding in particular I think someone needs to go through carefully to determine what should get feeding, and I don't have time to do so right now.
I'm necromancing this thread from its premature burial because pov_ass still makes no sense. Currently there's no point of view indication in the vast majority of the pictures tagged under it.
I think a mass-update from it to the ass tag or, as another user suggested, the introduction of an ass focus tag, works better than the current predicament, but I'd like to gather opinions before moving forward.