The only part of your body you can tickle yourself, is the roof of your mouth…
and… You could fit the entire human race in the volume of a sugar cube, this is because atoms are 99.9999999999999% empty space. If you could squeeze all the empty space out of all the atoms in all the 7 billion people in the world, you could indeed fit them in the volume of a sugar cube.
or.. You are 95% alien, 95% of the cells in your body do not belong to you. They are microorganisms hitching a ride. Many are essential like the gut bacteria that help you digest your food. You get all the alien microorganism only after you are born – from your mother’s milk and the environment. You are born 100% human but die 95% alien!