Answer:
Long and think, red within, with a nail at the end.
Talks like this, a green wise man does. Guess my clue, you will.
Something wholly unreal, yet seems real to I. Think my friend, tell me where does it lie?
They're up near the sky, on something very tall. Sometimes they die, only then do they fall.
What is the thing which, once poured out, cannot be gathered again?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?