blood effecting dreams?

I was laying down on my back stoned today and was thinking about how in castenedas book he said you can fall asleep in a dream in the same position you are sleeping in waking life to make the dream solid and stable. He called it the second gate of dreaming.
Then I was thinking about how when we are standing most of the blood is in our legs. And when you lay down and get up fast and it makes you semi black out because the blood rushs out of your head. then I was thinking how the right brain is the more artistic and intutive side of your brain and the left side is more logical. When that must mean when we sleep on one side the blood must pool onto one side of our brain more than the other. So I was wondering if falling asleep on the left or the right side, would we use that side of our brain more? Do you think this effects our dreams? If it does maybe we can sleep on the side that increases our odds of becoming lucid:-?

I think your right because my lucid dreams were more common if i slept on my right side.