Female menstruation is sacred to many indigenous Australian cultures because it distinguishes the time when a female is capable of bringing life into the world, putting a woman on the same level of creative abilities as the Rainbow Serpent. It is for this reason that men will attempt to mimic this holy process by cutting their arms and/or penises and letting their blood run over their own bodies, each other's bodies, and even into a woman's uterus. Men will sometimes mix their blood with a women's menstrual blood, letting them flow together in a ceremonial unification of the sexes.