Hi ED,
If my memory serves me well, I dont think my tutor used the name - sun/moon stroke, but then I could be wrong...
If this is the stroke you mean, its particulary used on the abdomen....
1. Place left hand on abdomen over navel area, rotate in a clockwise circling motion
2. bring right hand into play also using the circling clockwise motion, gliding your right hand over your left in a continuous circling movement.
I remember having trouble with this one myself when I was learning, its getting the co-ordination right.