In Gateway to the Inner Self, Waggoner mentions speaking with the awareness behind the dream(a sort of conscious being that is creating the dream) and getting responses.

An example was when he asked what the symbolism of a certain DC was, and a voice boomed from within the dream that answered. He asked to clarify, and it voiced again.

Has anyone experienced this? And what did you learn/gain from it?

I think in one dream I heard the voice and felt its presence as well, here is the link.