Playing the Bones
Adventures with 'other' instruments...
As I understand it, Gorilla snot is a form of rosin, so I guess a cake of rosin made for use by violinists would work too. I'm certain they will have that at my local music store. There is a pretty interesting entry for Rosin, which includes the many uses of rosin in our lives, on Wikipedia. If you’re interested.
(I am finding that as I improve my grip on the bones, there is considerably less slippage.)