Myrrh isn't really a chewing gum, moreso a resinous material which can be used as both a binder and a scent. It's often used in incense along with other resins and gums like copal. Other examples of gums include gum Arabic and xanthan gum
And frankincense, one of two other gifts of the magi. The third is unaromatic gold, of course. Here's some jewelry and a bunch of funeral scents kid, hope your step-dad got you a toy.
Seems like calling Myrrh “chewing gum” would be akin to calling a factory-new Bugatti Chiron “a busted-ass jalopy”. Which, depending on whom you’re talking to, is exactly what the Bugatti might be, I reckon.
"Er, well, um, if you're dropping by again, do pop in. Heh. And thanks a lot for the gold and frankincense, er, but don't worry too much about the myrrh next time. All right? Heh. Thank you. Good-bye."