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1.
A well aged, but not old, vagina that one encounters once in his/her lifetime. A distinct smell accompanies you and your belongings for an indefinite amount of time, usually days but if your lucky, weeks. Mossyjaw has been studied and test results have conclusively returned the following: 1) The fragrance/odor can't be removed with scrubbing pad and detergent alone. BLEACH MUST be used with the recipe. 2) Some may encounter post traumatic stress disorders after experiencing a good batch of the M-jaw (street slang). 3) If properly handled Mossyjaw can be a positive and life changing event in one's life.
I didn't see it coming, but just as her panties came down I understood with contentment that I was all up into some Mossyjaw. I scrubbed the next day for hours but that stuff wouldn't come-off, even with ajax and sos pad! M-jaw for life!
by Kalibama December 25, 2009
 
2.
Southern slang term for eating out a women's vagina. Mossy pertaining to the genetailia. Jaw pertaining to your mouth.
I sure did have some good mossy jaw last night.

by Kenny G August 23, 2006