Hi there, yes, I put a tutorial quite some time ago here. Here it is, it works a great for me. I use it a lot. Try others recommended as well as there are a few fail-safe ones out there :)
http://cakesdecor.com/entries/1954-making-modelling-chocolate
It’s on my Facebook page as well
https://www.facebook.com/media/set/?set=a.836764223037802.1073741898.162378177143080&type=3
You must never limit your challenges, instead you must challenge your limits
