The best way to keep the chair mat from sliding is to apply double tape on the lower side of the mat. A double-tap will stick to the bottom of the mat and the floor, keeping it in place for as long as the stickiness is there. However, it works better with certain floors like wooden or any other type of bare floor. It can work fine on the carpet for a while but will damage the carper fur, look and feel, and sometimes cause tearing to the expensive carpet. Therefore, in such cases, look for alternative options.