ANSWER: I taught my pugs not to do that by playing with them nicely but with my hands in fists so there was really nothing they could get a hold of if they did expose their teeth. They soon figure out I can’t pet them without my fingers and I’m not taking my fingers out until they are safe. I also use a universal sound that sounds like a telephone busy signal if someone is cutting up. That sound will stop all four fo them in their tracks to await further instructions – like ‘no teeth’ or ‘outside’ or whatever. For Pete’s sake don’t hit them at all and don’t use their crate for correction! That is their bed.