How about a tag for full_cleavage?

Something like:

When a woman is wearing clothing which covers both breasts but leaves their cleavage completely unobstructed.

Does not apply to a topless female or when a female character is viewed downblouse.

Are you thinking of plunging neckline?

Partially. That tag encompasses a lot of what I'm thinking.

It doesn't seem that plunging neckline would apply to this post, though, and it's the post which prompted my question:

post #10761720

Plus, clothing with a plunging neckline doesn't necessarily indicate that the full cleavage is visible; the art could be a side view, or the person's chest could be behind something they're holding.