It took me about 10 long years of practice, yes it was very scary when it happen, when it ended i felt so tired.
I decided one day i was going to try it again because I wanted to see my son that was in Texas, i was living in Florida, i actually saw my self in my son's hotel room sitting in this green chair he was a sleep when i came back the phone rang it was my son telling me if i was ok i ask him why he said he had a dream with me that i was sitting in his room! i told him he wasn't dreaming, i told him i was sitting in a green chair he said Mom! how did you know that, I reply again honey i was in your room.
So you see is just practice, practice.