Answer:
What do you have in December that you don't have in any other month?
You fill it and it empties, A metaphor for plenty, Depending on what half you see, It's either full or empty
What is it that no man ever saw, which never was, but always will be?
Everybody's got one.
You can't keep this until you have given it. What is it?
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?