look up any word, like eight ball:
 
1.
A poon prune is when someones hand looks pruney like it's been soaked in water for too long after he or she has fingered someone repetitively. Hence, the word poon as in poon tang instead of vagina or pussy, since it rhymes with prune.
His girlfriend was definitely happy by the look of that poon prune right hand.
by tehalikat January 03, 2008
 
2.
1. When a lady leaves her tampon in her vag too long...it turns into a poon prune.

2. The wrinkled vagina of an elderly person that has aged to perfection.

3. When your body displaces a bowel movement, and the excrement channels itself out of the vagina instead of the anus. The resulting waste is poon prune.
Forgot to take out my tampon before having sex last night. Pulled it out today, and it was a big, juicy poon prune!
by Hanhuddleyston Bros. February 09, 2010