(n) The practice of rinsing the vaginal vault with a carbonated beverage, such as a cola drink. The can or bottle is usually agitated vigorously post coitus, and the ensuing spray is directed towards the vaginal opening. In the 1950s, prior to availability of the oral contraceptive pill, this was considered a form of birth control, and Coca cola was thought to have some spermicidal properties. Referred to in the song "Coca Cola Douche" by 60s New York band, The Fugs.
Archie: Oh no, my rubber burst!
Betty: Never mind, give me a Coca Cola douche.