What you are looking for is "Pharmaceutical Grade" anise oil. Check with your local pharmacists (particularly the ones that do "compounding")....not that many carry it, so you may have to hunt a bit. The stuff in the supermarket is not the same.

By the way, regarding nightcrawlers, as a kid I inadvertantly tasted many worms after baiting my hook and picking up a sandwich without washing my hands....worms DO NOT taste like anise/licorice, trust me! The taste is distinct and unforgetable.