Fair question, i feel alot of us run into situations in which you want to "protect" or "Make sure" your HB doesnt get taken away.
That already stems from an insecurity. That means you think you're girl will be snapped away or something.
Not true. The only way this'll happen is if she smells your insecurity and gets turned off by it.
In your situation in particular it seems that a guy was annoying. Thats a bit strange.
But what you can do is ask the girl directly "Who is he?"
If she says "Random weirdo just wont go away"
Tell her directly "Tell him to go away"
If he wont go away , tell him yourself in a friendly way. If he wont go away after that, go tell security.
Problem solved.
I've done thousands of approaches in my life and that has never happened to me.
Useually a guy realizes pretty quickly she is with you and goes away.
But girls are smart. They know how to get rid of annoying guys.
The more you go out and socialize the more you'll understand, these situations are not a big deal at all.
Play it cool and dont get in fights, use your head and common sense to disarm obstacles, pick up is ultimately a game of wits.
(i'm personally a guy who rather punch first and ask questions later, but in the game you must control yourself if you want to succeed) Actually in life in general.
Make love not war.
Meditation helps with this. I recommend it. It has been proven to help increase focus.
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