A douche (/ˈduːʃ/) is a device used to introduce a stream of water into the body for medical or hygienic reasons, or the stream of water itself.
Douche usually refers to vaginal irrigation, the rinsing of the vagina, but it can also refer to the rinsing of any body cavity. A douche bag is a piece of equipment for douching—a bag for holding the fluid used in douching. To avoid transferring intestinal bacteria into the vagina, the same bag must not be used for an enema and a vaginal douche.
Douching after sexual intercourse is not an effective form of birth control. Additionally douching is associated with a number of health problems (cervical cancer, pelvic inflammatory disease, endometritis, and increased risk of sexually transmitted infections) and thus is not recommended.(Wikipedia)