Answer:
You fill it and it empties, A metaphor for plenty, Depending on what half you see, It's either full or empty
These are the bumpy parts of your digits
If someone calls you this, it might be time to consider hot wax
Without what would everyone lose their head?
Usually green but can be brown. It's a great place to play or lie down. What is it?
What is 9 added to any number ending in 1