Answer:
Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.
Runs smoother than any rhyme, loves to fall but cannot climb!
What surrounds the world, yet dwells within a thimble?
A leathery snake, with a stinging bite. I'll stay coiled up, unless I must fight.
What runs around all day. Then lies under the bed. With its tongue hanging out?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?