It worked once for me, but back then I didn't know anything about lucid dreaming so I couldn't take advantage of it. Was actually pretty much by accident. I haven't tried this again but I suppose I could.

And about the position... It's a little hard to explain but the angle should be pretty high... because the higher it is the harder it is to keep the hand up. You'll have to optimize it. A lower angle means more pressure on the wall, making the position pretty stable... which is bad.