A dog that intends to bite does not bare its teeth.
I learned this one the hard way. Cooper's bitten me several times, but not recently and usually just when he's teething. I think he's bitten John once or twice. He's never bitten another kid. Until last week.
We spent a few days with my parents, Dayna, Zak, & Caycee. Within hours of me & Cooper arriving, he & Caycee had a small tiff & suddenly she was screaming. I had no idea what happened until I saw her face start to turn red. Yep, he bit her on the face. What is wrong with my child? He bit several more times, & made several attempts. Time-outs didn't work at all (he laughed & played), so he got swatted on the butt a couple times. That seemed to get the message across at least. Luckily, Zak & Caycee (& Dayna) were very forgiving, although Zak & Caycee did yell, "Don't bite me!" when Cooper would chase them. I guess I can't blame them.