A great way to master your cycle is to sync it with the cycles of the moon. Many years ago I did a practice that synched me in with the moon. I began to leave the curtains open for three nights around the full moon and slept witt the light of the full moon coming in, and closed and slept in total darkness the three nights around the new moon. Soon I started to bleed either around the new or the full moon depending on the season. It would shift for a month or two when the seasons changed.