TENS stands for transcutaneous electrical nerve stimulation. Transcutaneous means across the skin. TENS is also called electrotherapy.The TENS current passes electricity across the skin to stimulate the nerves and relieve pain. Small electrodes are put on the skin, and the electrodes are connected to the TENS device (Comfee) blocking pain signals by stimulating different nerves in the spinal cord. TENS also cause the release of endorphins — the body's natural pain relievers.