I've been conditioning myself for WILD by trying it at night (to become more focused during the real thing and get used to the process) and attempting it every so often after 5-6 hours of sleep.

Here is a summary of what i've experienced during my attempts:
A tingling feeling in my feet and hands very similar to when they "fall asleep" but it goes away entirely if I completely open my eyes and sit up.
After a while it becomes difficult to move my body (although if I break my concentration I can do it)
Sometimes I see flashing patterns of blue light in front of my eyes (they're closed but the lights appeared to be 1-3" away)
A feeling that my body is spinning or that my hands and feet are lighter than air and are beginning to levitate very slowly, sometimes I'll even feel weightless.
My eyes feel like they're moving quickly almost like they're trembling or jumping up and down.
My limbs, neck and sometimes back feel like they're trembling and last night it felt like a wave or pulse was going through my arm (it's hard to explain)
Last night there were a couple of times when it felt like the blackness when you close your eyes had been pulled into my head or my eyes (I'm not sure how to describe it because it's kind of hazy and usually my body felt like it was floating or spinning.)

Most of what is listed above usually occurs when I concentrate on the counting and pay no attention to my body. I'm wondering if I was meditating or had in fact fallen asleep without knowing it.