Many people, including those who menstruate, harbour wrong ideas about periods. One common misconception is that the blood flows continuously during menstruation, like water from an opened tap. In reality, menstrual blood is discharged from the vagina in waves, explains Berlin-based gynaecologist Mandy Mangler. Some women are able to train their pelvic floor so they are able to menstruate intentionally at a certain time, for example when they are going to the toilet. Menstruating without using period products is known as free bleeding, a practice that has been prominently used by female athlet…