Answer:
When I live I cry if you don't kill me I'll die.
The more you take of me the more you leave behind.
I am rarely touched but often held. If you are smart you'll use me well. What am I?
If you have me you want to share me. Once you share me you wonβt have me.
I am the ultimate killing machine used not once but TWICE I can be made by humans.
I go in hard come out soft. Blow me hard and Iβll make a pop.