The RC that works everytime, it's always w/you!

I find that the best Reality Check is your own body. It's always there and you can't make up crap about why it's morphed! (like you can with the light switch RC that doesn't work - they mal function in real life along with other RCs that truly don't work - at least not as well as this one does.)

I would start out simple like counting fingers or memorizing where freckles or permanent things are like birth marks.

That and to become aware of your body movements/joints, touch (hot/cold, pain etc.) taste, sight, smell - but the best one is by looking down at your own body (sight). Counting fingers, noticing the location of things (such as your thumbs are in the middle when you see the tops of your hands.) Even looking at your fingernails, veins visible on your skin.

I would also recommed the Feldenkrais method which makes you super aware of your body. Most people aren't aware of the skin they walk in everyday!! People mostly focus their attention on external things, what they see, hear, etc - but they even zone out most sounds and feelings (like your watch on your hand). So as much as you can during the day, focus inward - it's sort of a paradox - like lucid dreaming is - you become aware of the inner and the outer all at the same time. Don't believe me that it's hard? Then try it, close your eyes and you'll realize you slouch too much or drag your feet, clench your shoulders or teeth and hold your stomach in.

My own physical body, whenever I RC, I'm constantly aware of it, I think about it, I wonder, I feel, I touch, trying to make myself as "super aware" as possible.
Anything can be an RC, your body is always with you, so it's obviously a good choice for it. However, it does not always work, if you count your fingers you may find you really do have 5 fingers, and go on with your dream as if it were waking life. For this reason, I always try to have a backup RC, sometimes when im not sure of myself, I can have chains of 4, 5, 6 consecutive RCs. The point is, Yes your body can be an RC, but it may often fail. I hope that helps!

What I'm saying is, it's a way to become more conscious and lucid - always. Even normal RCs become habits. I'm hoping this will be somewhat of a way to be aware of your own awareness. The RCs become like learning to eat, speak, or whatever when you are 0-5 years old. You have to try so hard to learn and remember it, but before you know it - it becomes a habit. I have a post about "passive lucidity" that might be interesting for some of you :)

Oh I use something similar, gravity RC... to focus on how gravity feels on my body <.< Could use others, but I know they won't work lol