All the songs on Guitar Hero are "hard rock" songs. And because of that, some of the lyrics are a bit questionable...unfortunately Max can make out some of what they are saying (example)
He has been singing: "Chop the Salad Bar Invasion, Talk Dirty to Me"
Translation: "Lock the Cellar Door and baby, Talk Dirty to Me"
He's been singing it everywhere and it's hilarious.
Almost as hilarious as the time he started singing "She's my Cherry Pie" in the grocery store (unfortunately he got all those words correct!)