specifically the front teeth of canines!
Came across this lil video on twitter https://twitter.com/nywolforg/status/1331579639542722563 which beautifully shows how that whole nose area just slides up when snarling! Got me motivated to take a closer look at the whole business there! You can even see the nostrils flex
After all, I never really know what to do with the bottom teeth since they always are so hidden,, but now I have a bit of a better idea of what's going on - the upper row is in the front and the bottom lip isn't pulled down necessarily - also I keep underestimating the lip-structure!
And I have a grasp on the canines, but I still feel wonky freehanding the incisors - they still tend to look better when I stylize and simplify the whole shape,, so I'll probably need to take a look at some more pictures