A girl so fit that you'd go down on her first thing on a one-nighter regardless of her having a shower or not or how many piss-stops she's had during the night while out clubbing/on the lash. Derived from the same burning reaction you get from placing a nine volt battery on your tongue as what you get from going down on an unwashed beaver.
Look at her over there, is she a nine-volter or what?

(other possible uses are upping the voltage to say a 24volter if she's way up there, or likening her to a car battery)
by savageYfronts October 22, 2006
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"That bird from last night was a bit of a nine-volter"
"Be fair- she HAD been dancing all night"
by Azenath69 December 19, 2021
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