Menstruation is one of the last taboos but the 'net is sure changing all that.
There are now hundreds, if not thousands of site devoted to periods, from the esoteric to the raunchy. Periods can be funny, or embarassing, or annoying, or exhilarating. Lovers share periods. Some women like to masturbate during their periods. Maybe you know someone who does that, and you don't even know it.