Can anyone explain to me what's the deal with these pubic tats?
E.g. like this one: rule34.xxx/index.php?page=post&s=view&id=7963158

I see it pretty often (here). Sometimes they glow like here, which makes me think it comes from somewhere.
Is there some lore behind it? What's it about?

It's like a succubus mark and maybe glows when succubus uses their powers or are creampied. There are some vids for example that when the succubus makes the man hard their tats glow

It can also be a mind control sigil
Or a branding mark

Usually a glowing sigil there is dark magic of some sort. Most times it's a crest out on by a succubus or some sort of dark magic user, and it indicates that the bearer is under the control of that succubus and/or magic user.

Some people draw Zelda to have Triforce Pubes, like, not as a tat, but as pubes, which is more funny than hot