I don't recall seeing those wooden egg tops before. But this reminds me a true egg top from Don:
Spinning:
There is a little hole on the bottom (tip) from where the egg was emptied.
I'm not sure why he didn't do it on the side covered by the stem.This is a pretty fragile top, but at least it's not meant to be thrown. Yesterday I freestyled for the first time with a terracota top I got from Rocco
EDIT: I just checked with a flashlight and there is a bigger hole in the egg shell covered by the stem. I guess the little hole at the tip was made to let air in while draining from the other one.