BF
n.— «I have often been struck by the numbers of young men, in small towns as well as in metro cities, who say that much of their “knowledge” about sex has come from the study of what is so familiar that it has been reduced to the acronym, “BF”; which for the uninitiated means blue films.» —“Sex education and the free market” by Jeremy Seabrook in U.K. The Statesman (India) Mar. 26, 2005. (source: Double-Tongued Dictionary)