Could someone pretty pelase explain what this is? In order to get this do I simply need to wake up after 6hours sleep and then stay awake with my eyes close? Will it eventually grow in immensity and allow me to step in?
Thanks in advance for an explenation 
HI is simply images, sounds or body sensations you have just as you are falling a sleep. It might start off as just flashes of colors then shapes then images of people pr things until you start to see a moving picture in your head. You may also experience strange sounds.
Try this: Flip the surrounding lights off until it’s dark or dim. Stare at the computer screen for 10 secs or longer and shut your eyes. You should see the computer screen still, but it’ll slowly fade. When I do it, it’s a green box that fades out. This is where you see HI! As soon as you shut your eyes you see HI. Weird. I don’t know why, but hey. So for me, when I start to fall asleep it’s just lights shifting around and if I try to focus on them they disappear. Eventually, an image of someone will flash amongst all the lights. After that it’ll be a full scene, back to the lights, then longer scenes. These scenes eventually become dreams. I find that it helps to get the dreams going sooner by coming up with one and “daydreaming” (even though it might be at night…) instead of focusing on the HI. I really know when I’m about to fall asleep because pairs of eyes will repeatedly flash amongst the HI. Once I notice that I say “Here we go!” and a few minutes later, I’m out.
When you close your eyes and go to sleep, you can see a lot of little fuzzy light dots (they are called phosphenes). When you go deeper in sleep, you can sometimes see faces, landscapes, strange objects, etc. in front of your eyes. Generally, as soon as you notice them, they disappear. That’s hypnagogic imagery. If you don’t notice them, one of them become more stable, you generally loose consciousness and a dream begins.
When you practice WBTB, you’re more likely to see phosphenes (they are brighter and more coloured and textured) and HI. That’s probably due to brain chemistry.
There is a moment, when practising WILD or dream reentry, when you can sort of zoom, or go, into the HI and feel you’re surrounded by the background. Then you are in a LD.
Basilus, 
That was the hardest-core description of HI! Thanks! Now I really know what’s going on when I close my eyes.
Ya thats when I needed, Thanks Basilus 
So much compliments! I’m confused! 
Sometimes when using the WILD method you don’t even realise right away that you have you crossed over into a dream. It can be quite surprising to realise that you are suddenly interacting with the images and have been drawn into them instead of just being an observer. I’ve only been successfull with WILD three times so far, but it’s worth all the work you put into it - it’s a really crazy and amazing way to enter a lucid dream.