Yet another help with WILD thread.

Hey guys,
I've been trying the WILD technique lately and I seem to be having no success whatsoever.
Today I had an afternoon nap at 5.10 and attempted to WILD.
I laid on my back with my hands by my side and proceeded to lay there.
At times I felt itchs on my nose or foot or whatever, but I ignored them completely and remained perfectly still.

I guess I felt a feeling of slight heaviness after about 15 minutes from starting the attempt.
But other then that slight feeling, I did not feel anything else related to Sleep Paralysis.
I attempted to WILD for 50 minutes, without moving (apart from the occasional swallow of saliva, if that means anything) and am wondering why I am not experiencing anything else.

So my question is, what am I doing wrong?
Thanks :)