Sing Song

History

Hoomans used to believe that the planets and stars in the sky were alive. Since the distances are so far, they would sing to each other instead. So they began to sing to each other from fair distances.
It developed into Hoomans singing to their loved ones from places like other rooms or over the phone.

Execution

A hooman will just sing to another, usually in another room or somewhere they can't be seen. The only indication that a hooman is being sung to is if they enter the room or are seen by the singer.
The song will depend on the singing ability and preference of the singing hooman. Usually it's a song that both of them enjoy or has some significant meaning behind it.
There's probably hoomans that mess around with loved ones, like jumping in and out of the room to see if they'll sing again. Both kids and adults would do that.