short stack of nickels
A reference to the size of the male weener when it is extremely flaccid, and somewhat exposed. Most often accompanied by tighy whities, a t-shirt, spandex, a wetsuit or similar.
When my friend got out of the lake in a wetsuit, it was as though someone had placed a short stack of nickels in the area where his his genetalia should be. Everyone was made aware of this, and laughed histerically.