Standard Days Methodâ„¢. A new natural method of FP that is highly effective (95%) when used correctly. To use the method, couples avoid unprotected sex on days 8 through 19 of the womanâ€(tm)s menstrual cycle. Many women who use the SDM also use a string of color-coded beads, called CycleBeadsâ„¢, to track their fertile days