To reach climax prematurely. To cum short of things or fail in the end. To mess up or be an idiot.
Damn she was so fucking sexy that i fumble nutted in the car, on the way home.

Mike Carroll couldn't do the nollie kick flip 360, what a fumble nut.
The boy that cried wolf got eaten by wolves. Why? Because he's a fucking fumble nut.
by impressionable380 April 24, 2013
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