Songwriting is ... all about intuition - this thing pops into your head for a reason and it's up to you to follow it. It's like there's a spirit, or intuitive network, that comes through all of us, but most people don't take the time to think about it or remember it. These little things pop into our heads - it's just a process of intuition. The initial thought comes in a baby state, and you work on that some more.
