Circular breathing will not help you pass a breathalyzer test. It is physically impossible to move air from your nose to your mouth without it first going into your lungs. I suppose if you involved some tubing and a friend you might be able to pull it off, but I would not recommend that.
Even when circular breathing, you are still inhaling through the nose into the lungs and then exhaling out through the mouth. The reason you can create a continuous stream is because you exhale into your mouth from your lungs a little faster than you allow the air to leave your mouth. This causes your cheeks to inflate. Once your lungs are empty, you squeeze this left over air out of your mouth while inhaling quickly through your nose.
The didjeridu is not the only instrument that is played exclusively using circular breathing. The island of Sardinia has an ancient reed instrument called the Launeddas that is played in a similar fashion.