Blink: Yes, I actually found two! They just came, on different trips, and now they accompany me, or I "am" them.

Alysia: It was recommended to dance physically, but I can't do it here in my appartment, so I decided to do it in the visualized version of my bedroom. It became big, and everything started to live somehow.

OBEs/phasing and shamanic experiences is an interesting topic, to compare both. There are many similarities; I expect that people, who are experienced in phasing can have easily shamanic experiences; maybe they don't even need a drum; although, when acting physically at the same time, it might be better with a drum  to keep one in the shaman's state while acting (dancing or treating a patient).

Spooky

Blink  :
The book I've read is Michael Harner's "The Way Of The Shaman". According to Harner, the physical dancing enables your personal animal of power (a spirit) to enjoy the physical, so, when you regularly dance "it's" dance, it will stay with you and give you power. Typically, the shaman "becomes" partly this animal, mimicking it's movements in the dance.
  Also, when the shaman is dancing, he has a rattle and leads the rhythm for the drummer; this alltogether will put the shaman to a controlled trance.

  The suggested ritual contains turns to the east, south, west, north, up, down, rattle speed, the dance as a sacrifice and an attraction to the animals, the dance of the specific own animal of power. It's suggested to do it in a darkened, empty room.

Well, I have no empty room, and if I had, my neighbors would go crazy when I'd dance freely on my wooden floor, therefore I did it lying on my bed, in my mind, like I do my mind-journeys. My (visualized) room became wide, the remaining furniture and all moved, bent, as if alive, and I sensed many little critters all around, but they showed not up, and after a little while an animal appeared, so I danced it's dance, partly becoming it. I did not care much about to follow the ritual literally. The other animal I met on my mind-journey to the (shamanic) low world, which I did after that dance.

  I add an own thought: Shamanism is a practical thing, for healing (or witchcraft). Through this bodily activity the spiritual work is more likely to be effective, we could say, it is probably more "grounded" than without physical activity (especially when you treat someone).

Maybe the rock was/is used in shamanic rituals?

Spooky