Ren Allen

Ok, maybe this is too simplistic, but here is what I came up with;

Take a bicycle pump and some clear plastic tubing. The plastic tubing
is sold in the pond sections of home improvement stores, or a water
garden store. It's cheap and sold by the foot.
If you ran a piece from the pump, up under your volcano, then filled
the volcano with runny chocolate, I think it would work. Everytime you
pushed on the pump, you'd get some nice bubbles and run off. Just pump
gently to start with...I don't know if it could really send some goo
flying!! You might end up with chocolate on your ceiling.

Either way, it will be a great experiment.
It will be interesting to see what chocolate volcanoes lead into....

How inspirational! :)

Ren