Demain is another guy that inspires me.  I posted the above as a continuation of the pressure pass idea that Dave turned me on to and I subsequently saw BJ Penn using.  To me it looks like he just gets an underhook and head pressure.  From there the guy on bottom is playing catch up while Demian "floats" to an opening. This style of passing is so hard to deal with.
I think this also underscores proper posture from bottom in butterfly guard.  Marcelo emphasizes head in front of hips.  You can see that once you get this posture broken, you end up flat on your back, getting passed.

One last note, take a look at the position at 0:55 and you'll see BJ Penn gets to this spot in every pass.  Very dominant.  It is basically over at this point for the guard player.

I love watching top level guys.  Incredible.