I totally second the idea of a chile-flavored tea. Maybe Fresno or Habanero peppers? Or Serrano - those all have nice flavors. And if you remove the seeds and the core and use the flesh, they're not too hot and they still have all that wonderful flavor. (And I'll be able to drink it - I'm allergic to the seeds inside peppers.)
Teaspoon, your tea cozy is adorable! Please do post back letting us know how it holds heat once you've tried it out.