I find that when I`m in a Lucid dream in the morning as I become more aware I can feel myself waking up. I`ve been able to control this to some extent I find if I let go of control of the dream I drift deeper into sleep(I`m better at doing the opposite – I can always wake myself up from a dream). A few times my eyes have even opened and Ive been able to return to the lucid dream. But if I open my eyes and think about stuff even for a few seconds then I cannot get back to sleep.

I read somewhere that when we fall asleep naturally we fall into NREM and I thought this might explain why I can`t fall back to sleep (I`ve never kept awareness as I have fallen asleep at night so I think that I`m probably not skilled enough to keep awareness into NREM). If this is the case when I open my eyes briefly I am falling into REM sleep. So what determines whether the brain is capable of falling into REM directly?

Or does anyone have anything that works for them when they need to get back to sleep?
Or getting to sleep I the first place?

I understand that when you sleep in longer its going to get harder and harder to stay asleep but it would be a great skill for dreaming.