In the body, energy moves along pathways   called meridians, which flow like rivers. The energy, called qi, pools or rushes in precise anatomical locations called acupuncture points.  By way of thin needles, points can be affected.  The needles increase flow by removing obstacles, or adding boundaries to calm unruly currents.   Sterile single-use needles, slightly larger than a strand of hair, are inserted quickly under the skin, usually without sensation. An acupuncture treatment  can be a very comfortable and relaxing experience.  The needles may be gently moved to create a feeling of pressure, warmth, or tingling, this is called the arrival of qi, or the qi sensation.  An acupuncture treatment may also include:  moxibustion (the burning of herbs to warm the body), electrical stimulation (usually used for pain), or cupping (the stimulation of points with suction cups).