Via advertising-hints tweets (here & he got it from groundswellblog), I found a call to stencil with mud. Yes, Mud. There's even a blog dedicated to it :Mudstencils - where you can pick up tips on how to create the best mud.
Once I fought the urge to scream "damn hippies" I soon realized this is the ultimate media for Wisk worldwide. Dirt is good! Keep your eyes peeled for a mud stencil ad near you soon.