How to make something look bubbly and shaky

I’m getting back into Flash after a six year hiatus (I was going a little crazy with it so my mum decided to take it from me until my marks caught-up), and I’m feeling rusty. I’ve been trying to do this for practice.

If you head onto the Grumpy Gamer comics and play them, you’ll see what I mean: I’m trying to do that wobbly, sort of liquidy feeling the characters are doing. I can’t figure-out how to do it though; masks? I’m not sure…Help is really really appreciated!

:bu: <-- lol awesome emoticon