When I was growing up I used play a game called, "What would it look like if I died right now?" The conceit of the game was to freeze what I was doing and think about all the muscles that were employed at that frozen moment and then watch as they released their function and I crumpled to the floor, slumped on the couch, lost my head into my plate and so on. The challenge of the game was to go for reality rather than drama. No melodramaticly thrown back heads or drooping tounges. It was a very slow and very mindful game. I always started with the most major muscle at the moment, I am only talking in terms of muscle muscles here, not smooth muscles and others kinds of muscles (the heart is the largest muscle in the body, muscle weighs more than fat, February is the shortest month, whatever.) Muscles that hold you up those are what I am talking about.
So, if I was sitting on the couch I would just start to give into gravity, releasing the tension in my legs and back and neck. Once the outline of what my lifeless shape was established, it was time to really scan and see the other places that weren't dead yet. Right shoulder lets go, jaw relaxes, ankle all those things. Sometimes things wouldn't move at all. Right now if I died, my arms wouldn't leave the laptop because of how I am propped up here on the couch, but my neck would relax and my head would fall to the left, then forward but not all the way to the laptop because there would be no backward momentum to propel the body forward. The force of my head fall forward is not enough to move the upper torso. And since it fell to the left first and then swung forward it lost a lot of the energy in the fall to the left.
Then I would lay there.