I wanna know how to become partially possessed not fully possessed lol 
I’ve searched on the forum and haven’t found anything that fully explains the process
If I’m not mistaken, EA’s book works of darkness covers it quite a bit. It has been a few years since I read the book so I don’t recall fully. Either the works of darkness, or The Book of Azazel might cover possession. I pretty sure the Voudon book covers it, but I wouldn’t recommand Voudon unless your fully commited to the practice.
Now my memories emerge,
The book of Azazel does cover possession, at least from what I can remember the experience of possession between EA and Azazel I think.
You have to practice , try invocation rituals and tell the spirit what if is you desire , that’s how it is