Over the last year or so I've noticed that when I'm having a conversation (not even hitting on, just talking about work/school/etc.) with a female (of all ages: 18 - 50+), they habitually (instinctively?) pull their shirt up as if to cover up their cleavage. This happens regardless of whether they are wearing a low cut shirt or not. Regardless of whether they actually have cleavage or not.

I should add, I am good at making/maintaining strong eye contact. And know for sure, that my eye aren't actually drifting downwards as if to stare at their cleavage.

So, I ask this Subreddit: What is this body language signifying? Is it positive or negative?

Thanks y'all.