While the classic "rocker sign" is usually a hand gesture, it can also be a few simple keystrokes. Using a combination of symbols available on your computer keyboard, you can convey a number of different gestures, including "Rock On!" or the "Devil's Horns" -- also known as the rocker sign. That combination of keys is the same on Facebook as it would be in any typed communication.
Log in to Facebook with your username and password.
Type "\m/" into your status update. If you want to do a "double devil's horn," type "\m/" twice, with one space in between.
Click "Share" to send the rocker sign or "devil's horns" message out to all of your friends and family.