Combine your water and chocoalte together in a bowl.
Microwave in 30 second incredments until the chocolat is soft.
Whisk it together until smooth. Microwave it more if needed.
Set your water ganache aside to cool to about 90ºF.
Combine your gold dust and oil together to make a thick paste. Adjust the amount of oil as needed.
Using a paintbrush, coat the bottom few inches of a piping bag with your paste. Make it very thick.
Pour your cooled water ganache into the piping bag.
Snip off the tip and pipe your gold drip onto your chilled cake.
Video
Notes
You can use any kind of chocolate for this dripLet your ganache cool a bit before piping for the best dripsMake sure your paste is very thick and you coat the inside of your piping bag wellDon't snip the hole of the piping bag too big