Now here's the fun part. Create a new action for your character, and bring up the pose sliders (alt-3). You'll see a range of sliders with the names you chose earlier:

Scrub the hmmf-jaw slider. predicably, your character will move between those extremes. Now leaving that slider pushed to -100% (a full hmmf), start slowly scrubbing the 'ooo-eee' slider. With around 60%, you should get something like this:

You'll find that setting two or more sliders to 100% will often look crap, but setting them to lesser values will get some nice results. Here's some settings I came up with: