Cervix And Period How Many Days Before My Period Is My Cervix Supposed To Open? (sorry Tmi!)?

How many days before my period is my cervix supposed to open? (sorry tmi!)? - cervix and period

I do not know if I Preggo or not, and I have recently learned that a few days before my time, will be used to float my cervix. I wonder how many days in advance that it would be.