Don't use a popsicle stick!
Ok, yes, a popsicle stick will work for your creasing needs, but this bone folder from Martha Stewart does a better job. Made of sturdy melamine, it can be used for brayering, creasing, and even rub-on applications. I use mine almost every single time I sit down to craft. It feels smooth to the touch and won't bend as you use it (like some cheaper bone folders).