Unentered vagina, virgin pussy, muff that has never been descended upon, uncharted territory, uneaten pie.
One must have utmost respect for the mystery-muff and only go diving if he wishes to partake in the activities of it for at least another week, seeing as though the availability of such is diminished in urban society.
When demystified you will know as it bleeds for short periods of time, perhaps half a day, and is a mystery to men no longer.
Still classified as mystery no matter what amount of diving one is involved in.
Sometimes used by ho bags to try and convince people to engage them without the use of disinfectant. (see: ho bag)
Sometimes one may refer to the virgin herself as mystery muff.
Can you believe the tits on that mystery-muff? I am gonna hit that shit on this trip baby! Oh Yeah!