Answer:
I am used when you jump off a bridge for fun.
If you're looking for something sweet I know what to do. But if you don't like heat I'm not for you.
I have 24 keys but cannot open any locks. Sometimes loud sometimes soft
I wiggle and cannot see; sometimes underground and sometimes on a tree. I really don't want to be on a hook and I become a person when combined with “book”.
When I am alive, people sing. When I am dead, people clap hands. What am I?
What sphinxes employ and players enjoy.