A turtlefuck is a little-known sex position that is slightly more complicated than most. It requires that both participants wear turtleshells large enough to place themselves in (this usually means a fake or synthetic turleshell). The actually sex must be done almost doggystyle but with the shells on, and VERY slowly. This cannot be stressed enough as any rapid movement in the turtlefuck will make it unsuccessful. And green paint may be needed in some very VERY special circumstances. Also, there must be a song about turtles, a cartoon featuring turtles, or a large poster with a turtle on it. Or, in ideal situations for a turtlefuck, there may be as many as 500 live turtles in the immediate vicinity of the turtlefuck(s).
A common misconception about the turtlefuck is that it does not alter the birth of children. A good example is how most people believe the Teenage Ninja Turtles to be the result of some crazy radioactive shit and turtles. The truth of the matter is that the Teenage Ninja Turtles are the result of a highly successfull turltefuck between Chuck Norris and Wonderwoman.
Turtlefuck is also sometimes a term used to a person. see the example 1.
2-He/She is down for a good ol' turtlefuck.
3-Hey baby, i got the shells, time for a TURLTEFUCK!