Answer:
Squash and Stretch in animation (S'nS) are a more functional way to make the character you are animating come to life or become more like a cartoon. For example, a ball. You can squash it to make it look like it is going down, and stretch it to make it look like it is going up. This creates the squash and stretch motion.
(my opinion about this technique. I like to use it to make it look more clear and bouncy.)
