If you tattoo it on your back then you won't see it
It would be good, "stay hungry" inner left forearm and "stay foolish" inner right forearm.
Stay foolish doesn't really resonate for me, but stay hunger does... hehehe and I don't mean it in a joke. I've always felt it in my being of absorbing knowledge as much as I can. Hungry for more knowledge and hungry for more life experience.
Not quite sure yet what you mean by how to apply to the world. Do you mean how I, being hungry for knowledge can help the world?... hmmm not quite sure of that one yet.