I am sorry to inform Sybil that he (she?) is terribly misinformed. And you, dear Trouble, are bandying about very dangerous ideas.
There is only one way to make a Marfouffe, and that involves stirring. Not shaking, wiggling, jiggling, bumping, jarring, or otherwise physically agitating except in the case of stirring.

The reason for this is quite simple, and relates to the derivation of the name Marfouffe (or Mah Fouf in Arabic). The name "Mah Fouf" derives from "mahlfouf," a dumbek rhythm sometimes played during spirit possession rituals involving the ingestion of Mah Fouf. "Mahlfouf" in Arabic means to wrap or spin around. This wrapping/spinning refers not only to the rhythmic pattern and the dance movements associated with this rhythm, but also, and most importantly, to the fact that the drink is always stirred, preferably with a long-handled spoon.

Modern variations may employ the industrial-power blender or electric mixers. That's okee-dokee by me, but I still prefer spoons.

I'm off to make some jello shots.