Tantric massage is basically just a massage. However it was created from the belief that if you are sexually happy and relaxed then your health will benefit. The Hindus describe Tantra as achieving personal growth through pleasurable existence. The massage itself does tend to cause orgasms, but these are described as a bonus rather than the aim.
Although Tantric massage does not involve actual penetrative sex, it does involve full on touching of the organs. For this reason you will not find it offered down your local health centre.
The Tantric massage will make you feel as if you are in a trance, where physical boundaries dissolve, time disappears, worries and problems no longer seem important, or are forgotten altogether if done properly.