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3.
The act of playing the guitar in a way that is gratuitously self-indulgent, yet enjoyable and compelling to watch. Often includes facial movements to indicate the difficulty or sexuality of a solo.
Jeepers, have you seen Steve Vai's "Tender Surrender" video? It's practically spadgetastic!
by Max Cummings October 30, 2003
 
1.
2. when a guitarist plays an excessivly virtuoso solo which dominates (and often ruins) the song, or at least a hefty proportion of it.

Either derives from the same thing as the previous definition, or from the fact that the guitarist in question is playing their solo so vehemently that they seem to be in love with themselves, and so are receiving (metaphorical) sexual pleasure from playing it (as one does when wanking)
Same as other definition
by Sue Denim January 22, 2005
 
2.
The art of playing twiddly crap sounding guitar solos , often with frantic wrist action , hence the comparison to wanking .
"all that fret wanking sounds shit"
by jess November 15, 2004