Answer:
I belong to you but others use me more often than you do. What am I?
My second is performed by my first. A thief by the marks of my whole might be caught. What am I?
I go in hard, come out soft. Blow me hard and I'll make a pop. What am I?
I am always hungry I must always be fed. The finger I lick will soon turn red.
You are my brother, but I am not your brother. Who am I?