Plexing was a Betazoid relaxation technique that consists of the stimulation of neural pressure points to relieve anxiety.
One plexing method that was effective for Humans is stimulation of the nerve cluster behind the carotid artery that stimulated a part of the brain that released natural endorphins. Troi taught this technique to Lieutenant Barclay to help him with his fear of transporters. (TNG: "Realm of Fear")