Answer:
Hold these between your knees if you want to set a Cuban beat.
It's anything but amusing when this body part gets hit.
A morbidlyยญ-named body of water
A box without hinges, lock or key, yet golden treasure lies within.
I open wide and tight I shut, Sharp am I and paper-cut fingers too, so do take care, I'm good and bad, so best beware.
I am your mother's brother's only brother in law. Who am I?