Sometimes, you just don't have time to straighten your hair with a straightener. When I'm in a rush, I use this simple way to straitened your hair with not heat.
Wet your brush, and brush it through your hair. Repeat this every hour, and you'll end up looking great, without a straightener!
Good luck!! It also works for touch ups, or getting your hair in a neat pony tail. If I somehow confused you, or you want to know what to do if you don't have a sink nearby, let me know!