There are a few reasons that may cause your TactJoy to slip on the surface of the touch-screen.
The screen itself could be oily or dirty. If that is a case simply clean the surface with a cloth or tissue.
The second reason could be that the special tape on the TactJoy is dirty. Every Tactjoy casing comes with an internal cleaning sticky pad that helps keep your TactJoy dust-free and clean for every use.
You may also use a normal scotch tape to clean the special tape on the TactJoy.
The videos below will show you how to maintain your TactJoy at tip-top condition.
