In Chan (Zen) temples back in the day monks played a game called "guest/host" in which they would practice verbally dueling with one another shifting between Guest (dualistic) and Host (non-dualistic) visions of r®eality as a way to show their understanding and learn from one another. What was it like? See the above! Thanks BE.
Perhaps the real purpose of mindfulness is simply to be effortlessly fully aware of one's own mind. And perhaps achieving that you are then equally effortlessly mindful of no thing and of everything...or now that I've said it, perhaps not! Dennis