hm i have done that a few times but not on purpose… itdidnt do anything for me… but then i nva really held it there long and now i am not even sure why i did it lol i miht try it in my next lucid and write back how it did hmm who knows just cuz it didnt do anything for me doesnt mean that it wont do anything for you
I don’t know about its effect in dreams, but irl this is an important step in chi practice. In the microcosmic orbit (see this topic) touching the palate with your tongue is necessary to link the two chi flows of the orbit (the front and back channels). Once chi flows through the palate and your tongue, you may feel tingling sensations. Perhaps you may even get a very sweet taste in your mouth.
It’s best to put the tongue at the back of the palate, this is the softest place and is known as the Heavenly Pool.
This might be an explanation of Castaneda’s technique. During LDs, things go a lot easier, so probably you will connect both channels at the palate more quickly (irl it takes a lots of practice).