A particularly filthy and/or sweaty vagina.

Could also refer to a Jammy Dodger that has been sitting in a warm lunchbox for too long, causing it to sweat.
Example 1

Guy1: "Wow she's a bit of alright!"
Guy2: "Don't go there man, she's got a Clammy Dodger"

Example 2

Guy1: "Ah mate, what the hell is that moist red blob in your lunchbox"
Guy2: "Clammy Dodger"
by ThompsonDB June 28, 2007
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