When performing this procedure, the acupuncturist inserts very fine needles under the skin at locations corresponding to a pressure point. Because the needles themselves are very thin, the patient experiences minimal discomfort. Before the insertion, the acupuncturist ensures that the needles are sterilized correctly to avoid infection. After the insertion, the needles may be gently moved or twirled to relieve any pressure or swelling that might be present in a particular area. In addition, the practitioner may also apply heat or a mild electric pulse to the needles inserted into the skin. Typically, they will remain in place for fifteen to thirty minutes while the patient lies still and relaxes. When removed, no sensation of discomfort is usually experienced.