In lucid dreaming, “the void” can mean a couple of different things in my experience. For one, Monroe refers to a “3D blackness”. This is not something that I have ever experienced myself, however it is discussed at length by other dreamers on forums. It seems to be a pitch blackness that has a three dimensional “feel” to it, and can be perceived in spatial terms rather than just as a flat blackness in front of the eyelids. It also seems that some areas of the darkness can be ‘blacker’ than others, even those it is all entirely pitch black. This is said to be a signpost that you’re on the way into dreaming or into an astral projection if you subscribe to that model.
Not only have I not experienced this particular phenomenon, but in fact I have never experienced any of the “signposts” that are associated with falling into dreaming or projection, so it’s really of no consequence if this sounds unfamiliar to you.
Another type of ‘void’ that I frequently experience is from a WILD attempt and when I ‘roll’ directly out of myself. I usually hit the floor and end up in a strange type of ‘colorful’ void. When I was first starting out, I would get the impression that my eyes were closed, and so I would try and force them open. All this did was wake me up in reality, and leave me awake and staring at my ceiling! The trick here instead, was to picture and imagine what I knew the floor where I had just landed to look like, and the surroundings from that point should begin to clear. Do not try to force your eyes open as I used to!
Lastly, the final type of void that I’ve experienced is when I try to move beyond the 1st dreaming state. As a thought responsive environment, any command or desire performed with intention will be instantly manifested. When I intend to speak with someone to learn information or similar, I am often ‘whooshed’ up right out of my dreamscape right into a colorful void, similar to the one described above. Although I can not describe the differences in words, this type of void has a distinctly different ‘feel’ to the one above, and so I categorize it differently.