The reason you do this is to give your muscle memory (your brain is a muscle too) a priority that while talking to girls you want to key in on their body language.
You want to do this for repeatedly, until it starts feeling natural.
She will lock eye contact with you, look down in a submissive way when she sees you are looking at her too, then a second later, look back up. Even though it’s not completely comfortable to lock eye contact so soon, she is feeling such attraction that she must see you again before you pass by.
If she looks back at you after passing (THC) THC is money with this.
As you go throughout your life, there are certain moments where you must know the answer to the question: does she like me?