I know all this, it burns with a waxy flame and has been used as a fuel for cooking. Stamping hot C4 out tends to make bad things happen though.
The only way to detonate it is with a huge electric shock.
No. Using a blasting cap is preferred. (Blasting caps are the bits you shouldn't be throwing around, they can take your fingers off.)
Actually, C4 is fire-safe. It burns, and emits toxic fumes, but it will burn in a controlled fashion w/o exploding.
I said throwing it onto a fire AND beating it, not either of the two. That's why Composition C and it's children are so fun to handle, because they don't detonate in your pocket.