When is it okay to tell an acquaintance they can't stare at my boobs?

No, really.

In a perfect world, it would be okay to tell them the very first time. In a perfect world I could yell back at cat-callers (or not get cat-called at all...also can someone write an article someday about the historical use of "cat" and "pussy" for bits, because I would absolutely read that) without being kind of concerned for my safety. In a perfect world, it wouldn't matter what women wore, because we never, ever, ever deserve it. *rant over*

In a perfect world, I would also get paid to drink wine, travel the world, and pin things on Pinterest all day too.

So I have this acquaintance, who I have to see professionally, on a relatively regular basis, cannot seem to look me in the eyes. They stare at my chest whether I'm in a tank top or a t-shirt or a dress or a coat - doesn't matter.

At first, I thought maybe I had something on myself. I am blessed in the boobs department, and yeah, I've absolutely dripped ranch on my boob before and not noticed until my friends mocked me (thanks y'all...). I'm a hot mess. It's not unrealistic to assume I have something out of place.

Nope.

All the time.

No ranch.

No crumbs.

No cat hair.

Just boobs.

I've tried everything short of saying don't look at my boobs. The "head bob down to wear this person looks" move. The "book in front of the chest" move. Even the "Oh...I gotta go" move, which just results in an awkward goodbye wave to the ladies, not me.

This person is not from this country, but I'm pretty sure no matter where you're from, you gotta look a girl in the eyes on occasion.

My career isn't dependent on them, but I work in a public setting and need to be at least cordial to everyone.

So when is the appropriate time?

A year?
A month?
A day?
2 years?
Never?
Whenever the hell I feel like it, ladylike demure-ing be damned?

Reason #672 why having boobs is hard, and #439 why being a woman is way more complicated than it should be/than most men recognize.