I am no master, and dictating via the internet is hard. But, I shall do my best.
One finger at a time, starting with the pinkie. Slowly stoke, in downward motion. Then bring your fingers back up in the same order. Your Pinkie and your pointer finger should be in unison once you get going. On the way down, lightly graze the skin of the 'lee with your fingertip and the very end of your fingernail if you fingernails are short; lightly flick the skin with your nails if you have long nails. On the way up, try and miss the 'lees flesh unless you have long nails.
Think of it, starting with your pinkie, 1-2-3-4, up, 1-2-3-4, up, and so on. Very speeds as to the reaction of your 'lee. Some people react to slow and torturous, while some can take fast and intense and others take everything between. But whether quick or slow, light and delicate dragging is the best.
On the stomach be sure to move around. Circle the navel and move to the sides. Also, check right where the ribs stop. Be sure to check the area right under the breasts with both men and women. That is usually a great spot.
That is all I have. Good luck.