from Urban Dictionary (God bless that website):
"Actually, that is a misconception. The urban myth purports that the practice originated in feudal Japan as a method of punishing women who had committed adultery. However, this is not true as the source is the imagination of the writer of a certain adult website who concocted the story to entice readers to subscribe
Bukkake is the noun form of the Japanese verb bukkakeru to dash water), and means simply "splash" or "dash." The compound verb can be decomposed into two verbs: butsu and kakeru . Butsu literally means to hit, but in this usage it appears to be an intensive prefix as in buttamageru, "completely astonished") or butchigiri , "overwhelming win"). Kakeru in this context means to shower or pour. The word bukkake is often used in Japanese to describe pouring out water (or other liquids) with sufficient momentum to cause splashing.
Indeed, bukkake is more commonly used in Japan to describe a type of dish where the toppings are poured on top of noodles, as in bukkake-udon and bukkake-soba."
