Answer:
It's anything but amusing when this body part gets hit.
As round as an apple. As deep as a cup. All the king's horses can't pull it up.
What comes once in a minute, twice in a moment, but never in a thousand years?
I bubble and laugh and spit water in your face. I am no lady, and I don't wear lace.
Dies half its life. Lives the rest. Dances without music. Breathes without breath.
I am the fountain from which no one can drink. For many I am considered a necessary link. Like gold to all I am sought for, but my continued death brings wealth for all to want more.