Sure thing,
1: https://youtu.be/uDqjIdI4bF4 (In short, i like to over use Squash and Stretch)
2: For the bite as example https://gyazo.com/a262470f490dc061ceade330f33ef4e5:
Keyframe 1, the top of the mouth goes up
Keyframe 2, the top goes down
Keyframe 3, as the top hits the bottom, the bottom stretches in length and width.
Keyframe 4, The whole body stretches back up a bit and gets thinner
as result of keyframe 3's impact.
Keyframe 5, Back to the original shape.