Undulating – applies to hills more than anything else I thought and so I found undulating hills. The last perhaps being too steep to undulate in the true sense of the word – smooth, wave-like motion. So can the sea with its waves moving in a definite smooth wave motion also be classified as undulating – ups and downs, peaks and valleys. I decide that it can.
So perhaps ripples on a pond or river also work as they too have ups and downs, a wave-like motion.
Music too has wave like motion, ups and downs, highs and lows and I have certainly heard the expression “she undulated to the music”. I remember at a dear friends 60th birthday a number of us were undulating to the music. Moving in a wave like motion.