You are in Member Communities . This can be to express emotion, to deal with feelings of unreality or numbness, to make flashbacks stop, to punish the self and stop self-hating thoughts, or to deal with a feeling of impending explosion.
SI is more about relieving tension or distress than is it about anything else.
Although cutting is the most common form of SI, burning and head-banging are also very common. That's why it sometimes seems to have addictive qualities. To help a client, you must offer more effective coping strategies as replacement. That phrase speaks to intent and maiming the body is usually not the intent of SI anyway. They never learned appropriate ways of expressing emotion and may have learned that emotions are bad and to be avoided.