Dear Divine Consciousness
Channelling is the use your mediumship, we dont use this term. Mediumship is very broad with several different types and is the proper name to be used. Those who use channelling dont have the study or knowledge about this subject.
Recent books are made by authors that discover some parts or process by their own experience. The most complete book about was writing more tham 150 years ago by huge efforts from many many mediums around the world and organized by Allan Kardec, yes was eleborated by the spirits!
The entire book The MediumĀ“s Book is the result and it is a complete compedium about this subject.
You can free download at:
www.ssbaltimore.org/PDF/Mediums.pdf
We are reincarnated spirits and we are here in material world to learn and through experiences we seek to evolve our morality and knowledge to reach perfection. Not in one single life time since this is impossible but coming and going thousands reincarnations...
"Tunning" is not the proper word too, but pse note that the phone rings from spiritual world to material world and not the way around, you can try to evoque, but depends on the spirits to accept a call.
Yes you can be possessed, it is a long and nasty process and hard to heal, this is very well described and see myself several times happened in young and non educated mediuns.
First of all you will never do this alone, there is a right place to do this and proper assistance material and spiritual assistance.
Why you are a medium? Because you asked for it! Yes, before you reincarnate you asked for something to put you in the right way o reach you goal in this life.
What to do with your mediumship? Help spirits (incarnated or not) you have to help them using for good and for free.
The proper place to develop and exercise your mediumship is in a Spiritist Center you can find one near you:
in US:
http://www.ssbaltimore.org/spiritist_centers.html
in UK:
http://bussuk.webs.com/spiritist-societies-uk
Other regions you must check
Dont forget as much as you study better you differenciate the class of spirits you are dealing with. Never stop studying!
Good study!