This occurs when an individual becomes zonked out on heroin or fentanyl while standing up. The upper body will be slumped over, bent at the waist and the arms will be hanging down towards the ground, giving the appearance of someone attempting to chew his or her own shoelaces.
"Hey, what's wrong with that guy over there in the alley?"
"Oh, just some idiot chewing on shoestrings."
When a person indulges too muchcrystal meth which causes their jaw to involuntarily move resembling the act of trying to get his shoulder into his mouth.
Poor guy was so high he was chewing on his shoulder and peeking out the blinds