What is Moxa?

What is that herb you are burning? Moxa or Ai Ye gets polarizing reviews as far as smell, the untrained nose will sometimes guess it is marijuana…not even close! I have always found it to give me a warm milk and honey like feeling. 
In practice it is used for warming and blood moving properties, menstrual cramps anyone?? It is also great for arthritic/bi pain, I can picture my mother leaning over the kitchen sink tracing her fingers before bed. If you want to know more below is a very entertaining interview with one of my favorite teachers!