How can I keep pillow cases from sliding off pillows?

When you wake up in the morning and find your pillows out of their pillow cases, there are several things that you can do to prevent this annoying little occurrence from happening. One is to sew some Velcro strips at the opening of the case in order to enclose the pillow and prevent it from falling out. Another similar solution is to change your cases to zip-on covers so you can totally enclose your pillows. You can also try getting covers that fit more snugly for your pillows if your current ones are too big. This could be the cause of your pillows sliding out of their respective pillow cases.