Answer:
What is something you can give away as many times you want without ever losing it?
What goes up and down the stairs without moving?
What is yours but only used by others?
In birth I spring forth, in life I unfold. In death I wilt and die, but rebirth restores all.
These are the bumpy parts of your digits
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?