What does it mean for girls to send HZ to boys?

We often use 52 Hz to describe a person who likes another person in love, but that person doesn't know it in his heart.

The word comes from the blue whale. 52 Hz is a special sound frequency. Generally, the blue whale will make a sound of 52 Hz to find a companion, but the body structure of the blue whale cannot receive the sound of this frequency.

So the blue whales in the sea are not in groups, they are all lonely, because they meet each other but never know each other's thoughts, so this is a very sad word.