That feeling between when you decide to lay down for a nap and actually falling asleep. When there's nothing on your mind, and you get your blankets just right, It's like coziness cranked to 11. One of my favorite sensations.
I love that too, especially the part when you have nothing at the back of your head bothering you. It's been quite some time since I have that feeling. Unfortunately, in my chaotic world, there is always something going on in my head.
Can I suggest the supplement L-Theanine? It's the chemical in tea that is associated with preventing people from getting the jitters from caffeine the way they do with coffee.
I have ADHD and anxiety, so I'm always thinking of something. It actually manages to mellow my brain out to be like, "Yeah, that's important...but is it productive to think about right now, this minute? Maybe not."
I even started taking it with my morning dose of Adderall because it tempers the intensity of the side effects.