Last time we talked about using flint and steel which is a really cool method and actually useful in real life situations.  Fire by friction is more temperamental and requires more technique and more patience.  It is a useful survival technique, but I don't go out of my way to make fires this way on purpose.  On the other hand, I use my steel quite often.

If you want to understand how fire by friction works, consider the time you slid down the slide at the playground and realized you were going way too fast. You tried to slow yourself down by grabbing the sides of the slide, but your hands soon became too hot to hold on. If you never had this experience, think about how warm your hands get sliding down the rope in the gym. Hot stuff, right?