Stand in a medium horse stance, with the feet two shoulder widths apart, back straight and the hands resting in front of the Dāntián 丹田. Lift up the hands up, the palms should face upwards until you reach the Middle Dāntián 中丹田 and then allow them to gradually turn over as the hands continue to rise up to a little higher than face height. The palms should now face out. Circle the hands away from you, so that both hands make a large circle in front of you. Bring the hands back down to the Dāntián and repeat the circle again. This means that the hands basically form a circle, rotating forwards. This forwards circle is Shùn Chán Sī Jìn 順纏絲勁. As the hands rise up, the body should also rise up and we should breathe in. As the hands come down, the body sinks and we should breathe out.
The Nì Chán Sī Jìn 逆纏絲勁 exercise is just the opposite. The beginning position is the same, with the hands in front of the Dāntián and the palms facing down. Begin to circle the hands away from you, with the palms facing out. As the hands come up to the face, roll the hands over so the palms face in. The hands continue to follow the circle and pass down the body, following the Rèn Mài 任脉, back to the Dāntián. Again as the hands come up the body should rise and we should breathe in, and as the hands drop down the body should sink and we should breathe out.
So the Shùn Chán Sī Jìn circles outwards and the Nì Chán Sī Jìn circles inwards. In these two exercises the legs do not move and only the hands and arms circle.