Can I put on a vaginal disc any day to postpone my period?

The way you want to act is not described as an option to postpone menstruation in the documentation of vaginal discs, so I can not recommend it. Such a procedure could possibly be recommended by a gynecologist, although if you do not care about contraception, but only about postponing the period, then there are other hormonal agents that serve this purpose. Starting the use of hormonal contraception in the form of a disc consists in the application on the first day of menstrual bleeding (on the first day of the cycle). You can also start between the 2nd and 5th day of menstruation, but in this case, during the first 7 days of using the disc, you should simultaneously use an additional method of contraception (such as a condom for men). If the patient does not want to have withdrawal bleeding (physiological menstruation during the use of hormones does not occur), then the onset of menstruation can be delayed by assuming a new vaginal therapeutic system immediately after removing the previous one, without a break in its use. This proceeding is admissible, although the manufacturer describes it as 'not recommended'. I enclose additional information: https://www.gdziepolek.pl/kategorie/krazki-dopochwowe