Esteemed guitarist John Mayer isn't so hot at Guitar Hero (which he mistakenly calls Rock Band). He reveals on Twitter that it's like "sex with a Real Doll."
Mayer also seems to think that he has to hold the guitar controller's strum bar down through each note. Once again, another musician doesn't seem immediately adept at Guitar Hero.
Funny enough, a year prior to this, John Mayer was bashing Guitar Hero.