Ultrasonic vibrations are used to modulate the friction coefficient between a sliding surface and the vibrating object. In this paper an ultrasonic travelling wave is used to modulate the friction accordingly to the direction of motion of the finger. In its propagation direction, the travelling wave applies a net force on the sliding body reducing the friction whereas in the other increases it. The ability to obtain an asymmetric friction coefficient in function of the motion direction has made possible to induce different sensation on the finger accordingly to the controlled direction of travelling wave.