There is not much guidance to give apart from what you already posted, namely, to release any fear and simply let it be.
What is occurring is during sleep; where the intellectual facility appears to be half asleep and half awake; is possible & ordinary. For example, I have experienced real wisdom engaging during dreams (generally about death); where wisdom engages and reflects: "This is only a dream".
As for the sensations, this is just mental formations moving around & arising to purify (what you call: "humming flow of energy flowing"). Again, there is not much guidance to give apart from what you already posted, namely, to release any fear and simply let it be.
Often, when my body-mind have releases of energy during sleep, the mind has dreams of literally flying in the sky; over oceans & cities at night; which is extremely enjoyable & refreshing. The mind can do these things because this is the creative or imaginative nature of the mind; that is all.
Also, the Buddhist scriptures mention supernormal mental occurrences, such as visions and perception of external events (called 'Divine Eye' & 'Divine Ear'). All of these things are mere possible mental happenings; that require release of any fear and simply let it be.
The core teaching of Buddhism is "non-attachment" towards all experience.
When a monk has heard that nothing is worth clinging to, he directly knows everything; having directly known everything, he fully understands everything; having directly known everything, he fully understood everything, whatever feeling he feels, whether pleasant or painful or neither pleasant or painful, he abides contemplating (observing) impermanence in those feelings, contemplating (observing) fading away, contemplating (observing) cessation, contemplating (observing) relinquishment (letting go). Contemplating (observing) thus, he does not cling (obsess about) to anything in the world.
