ICM stands for Intentional Camera Movement. It implies moving the camera during a long exposure. The photographer may shake, sweep, zoom, swing or rotate the camera body or do a combination of movements to achieve motion blur and an artistic effect. There is no clearly defined technique. Some photographers use a tripod and/or a flash, some do it hand-held. It's totally up to you... I love ICM because it's a journey into the unknown - beyond any boundaries...you never know what the result is going to be and the learning curve never stops.