In my Country Many believe that if you whistle at night, you invite snakes or malevolent spirits into your space.
I believe Parents often use this to keep children quiet in the evenings.
Thank you, we have lots of it to make us behave when I was growing up
That would make me be quiet and I’m a chatter box lol

I think you are right! Our parent may have made up of lot of these. This is a real scary one! Thanks for your comment and for your participation!