I just put whatever I want in a pocket or down a sleeve of my coat. I have a big coat, but even if you don't it's easy. You carry the coat over your arm with your stuff in a sleeve between your arm and your body, it's a flawless plan for anywhere that doesn't have actual security. Drinking out of a bottle isn't a lot better than drinking out of a flask though, but you will get a little more scent and flavor that way and it's simple enough. Loading up an insulated steel bottle with a wide mouth is better, but if you're not very graceful it can foam everywhere.