If any of them have there period they will completely understand! It will happen to them eventually! Period shouldn't be a shy thing! If it were me I wouldn't be scared to talk about it or ask questions
Not really necessary. Each one of them have periods and normal their ways. The right person to complain about period disorder is your doctor who will ascertain if really abnormal and need action or not.
Sometimes women talk about pink underclothes is better then black and certain writings are better than others. Yet we know most of the time they are covered.
The same thing about periods. They elate each other and depress each others too.