Don't call Bast a spirit or she'll scratch your eyes out. :p She's a goddess and one I worship. She's a goddess of joy and loves music and dancing. However, she is also a fierce goddess with a wrathful and dangerous side. After all, some of her epithets are "Devouring Lady" and "The Fiery One".
That said, you could try giving her some offerings of perfume, catnip and milk. She seems to like those things. She's actually very friendly to approach.
Calling her a goddess may or may not be accurate. A netjer/ntr/neter yes, but a goddess maybe not. The reason why is that oftentimes in ancient Egyptian cultural/spiritual practices, there isn't much difference between a netjer (a deity) and a netjeri (a non-human spirit). The term netjer/ntr/neter has been hypothesied to be connected to the term nature (to describe a spirit of nature or of a natural thing), while netjeri were given lesser jobs, such as of servants of the netjer (servants/fairies of a spirit of nature). Calling them fairies isn't entirely accurate, as fairies is a different culture's term, and also some of them aren't servants of a spirit of nature, but the group of them that I'm talking about is and could be compared to fairies.
So there is a Bast, there is a Bast-Mut, a Sekhmet-Bast-Ra, and there are Bast netjeri (who are a spirit of Bast/representative of Bast), etc. Just because the Bast you work with might be described as a goddess, doesn't mean every Bast is a goddess.
At least, that's all in relation to ancient Egypt and the Kemetic Orthodoxy. I'm sure a general recon slant will be different. :)