What is it about men who stare at a woman up and down, with eyes and mouth wide open?

Is that a good thing?
What kind of shocked or surprised is he?
What does it mean?

Is it being attractive to her or just lust?

And then after that walks slowly or drive slowly to keep looking at her.
Why is that?
What is it about men who stare at a woman up and down, with eyes and mouth wide open?
Post Opinion