If anyone's done any research before on Chinese Crested Dogs, one thing you may notice is that a lot of crestie owners say that the breed "smiles." Although I've fostered some back in the day, Tequila is the first crested where I actually realized what they meant, lol! I just figured, like, it was when (any breed really) was relaxed and panting, and the mouth is stretched open wide... any time you see 'smiling pet' photo contests or whatever that's what you see.
But no, a crested smile is a full fledged tooth-baring GRIN. Unlike growling, though, they don't actually make a sound, and they do it when they are excited, happy, enjoying a good scratch, or approaching you to cover you in kisses. Other breeds do it as well, but its apparently a pretty common trait in Chinese Cresteds. I don't think they figured out exactly WHY; I've heard that it's a sign of submission/respect and also heard that they are just mimicking us humans. Who knows. All I know is its the darned cutest thing ever... =D
Now when she comes up to us if we say "Is you's cheesin'?!" in a happy tone and she'll give us a big smile, tail a'waggin'. Enjoy!