Similar to a double down sandwich from KFC, this is the act of making a sandwich out of two tacos as the top and bottom and a jumbo jack from Jack in the Box in the middle.
This references to the Chewbacca character from Star Wars.
After his concert, the ghettorapperDaquan invited me to suck his dick. When he pulled out his 2 inch Chewbacock and shoved it in my mouth, I almost threw up