A meat chewer is a person who aggressively rides someone's meat so much to the point they end up becoming a nuisance to the person their meat riding and a bigger nuisance to other people.
Thus, chewing the meat.
"Luis is such a meat chewer he literally scared off Marcus"
"Zebra thingy" is another word for traffic light.
Used when an idiot doesn't know what a traffic light is called.
Mark: I'm going to be stuck here for hours because of this zebra thingy!
Dan: Zebra what?
Mark: Oh, I meant traffic light.