Hi everyone!
I've had about 4 or 5 lucid dreams in my life, and only two since I started using LD induction methods and reading tutorials on this site, but everyone of my LDs happened by pure chance.
Since on my last fortuitous lucid dream i was able to control the environment (by creating an elevator on a house) in a boost of confidence I decided to try and have some WILDS.
Obviously with no avail.
Here's what happened to me this last couple of times: I hope you can tell me if/what i'm doing wrong.

I lay down on my back and tell myself: "now i'm gonna Wild and i won't move a muscle"
then, usually, i picture stairs going down a hill, and i tell myself: "when I reach the bottom of the stairs i will be dreaming" and start counting the steps. Around the 100th steps i start losing counts and having HI.
BUT i can't stay lucid! After a while i inevitabily fall asleep and wake up after half an hour.
And here's a bizarre thing: when i'm having HI, my body moves on its own, my arms or legs have brief jerks that jolt me awake. But i'm keeping them still! why does this happens?
Why can't I consciously lucid dream?

i've also tried new techniques such as:
-frequently reality check
-reciting multiplication tables as I wild to keep my mind more lucid
-be more aware of my surroundings when i'm awake
-going to my mum and brothers (who appear very frequently in my dreams) and ask them: "is this a dream? how did we get here? how do we know this is not a dream"?

Nothing worked.

Can you help me out? Pretty pls? :3
and sorry for long ass post