Very often as I’m falling asleep I’ll get a feeling like rocking in a boat in the ocean, I think this is related to HI.
I dont think it is.
A lot of it is out of habbit methinks.
After spending a day on the water, when
i goto sleep my body has grown accustom
to the rocking and i will feel as if i am rocking
when i goto sleep.
I cannot sleep on my back. This is because as
an infant my mother never laid me down on
my back when i was to sleep, so my body grew
accustom to staying awake when i was on my
back, and sleeping when on my side or stomach.
The same can be said for rocking, if you were
frequently rocked to sleep as an infant or small
child your body will be accustom to the feelings
and sensations of being rocked before sleep,
oft times people who were “over-rocked” will
rock thems selves to sleep far into adulthood,
however others just facilitate the sensations.
c’est la vie
MAC
A lot of the time, when I realise I’m about to go to sleep, I notice that I start to spin… It’s really weird. Does anyone else get this? It’s happened since I was a kid.
Amy
I do that on purpose now and then, helps me relax and fall asleep fast. Also I use it when I WILD. Perhaps this happens automatically to you because it has become somewhat of a habit?
I try to do it diliberately, too. You’re probably right. It’s very easy to break, so I try to just encourage it and observe, like watching a wild animal in a glade.
How do you use it to WILD?
It’s more HH (hypnagogic hallucinations) than HI (imagery). It seems to me that it’s called a cenesthetic hallucination. The reason why is not clear. Sisokogotai is perhaps right, but it could be due to the activation of a center of the brain which is responsible for the sensation of movement during walking, or something like that. 
(I merged two topics as they had the same subject.)
I get that a lot too, like being on a giant swing, or swirling around like my room was spinning around. Sometimes it feels like the floor is really on the wall or the ceiling.
I think everyone experiences this to some extent. I do not think it is really HI or HH. It is just a symptom of you body and mind relaxing to let you fall asleep. Very often if I lay down and close my eyes within say a minute I will get a rocking, floating, falling or spinning feeling.
You can focus on this for WILD by trying to control these feelings. For me imagining falling or spinning are the most effective. Just imagine yourself falling or spinning and as you do so block all other thoughts out of your mind. If thoughts brake your concentration then gently bring your self back to your spinning or falling. Eventually it will not take much concentration to keep the spinning or falling and you will spin or fall right into your dreams. This works better if you put yourself in a state of alert relaxation first but it is not required. Often just the spinning or falling is enough to put yourself into a trance. For me rocking or floating does not work as well for me but feel free to experiment with that yourself and see what results you get.