Golden Bubba used to chew on little pebbles. Manny would say, "Bubba! Spit it out!" and Bub would spit. Literally spit.. Phtoo! and out would come the pebble.. He can spit it a foot in front of his mouth..lol
Now, it's easier if we see he has a rock in his mouth, and he sees us looking at him, he spits, or if we say,"buuuuubbbbbBah!" He spits.