I think it's Waffle House waitressspeak. You know, some code like "baby chicks with a bonnet" means eggs with cheese on top. Discuss.
There was a famous grafitti artist named Keith Haring that used chalk on subway trains. Actually the older ones we used to call Clunkers. They were dark and ugly, no air conditioning and loud. You could write on them better with chalk than spraypaint. Keith Haring went on to be a great artist that was honored around the world. He died at a young age.