On the last day of every month, close the blinds or curtains before you go to sleep. If during the middle of the night, you hear a tapping noise at the window, don't open your eyes.
If you're one of the unlucky ones, you'll hear a stone hit your window. It's not a friend, don't open your eyes.
The sound will get louder, the tapping will get faster. Don't open your eyes.
Don't let your curiosity get the better of you, don't move, it'll lose its patience, it will start thumping at the window. The window will start to shake and shudder, the noise will get louder. It will furiously pound on the window, the panes will start to shake, don't worry, it won't break. Just don't open your eyes.
No matter how scared you are, no matter how badly you want to scream, pretend you don't hear it, don't open your eyes.
The noise will stop, don't fall for it, don't open your eyes, try to sleep if you can. Don't get up, don't open your eyes until the sun comes up.
Those who do open their eyes... well, nobody knows