Today's xkcd comic combines cryptography and rap music.

It turns out the thinly disguised lyrics are from the chorus of the Missy Elliott song "Work it". Sorry I am not out scouring the urban format stations for musical hits, I had to look this one up on Google. There are a number commenters (one and two) on the joke and how they "got it", yet they failed to identify the particular song for the rap impaired. Here are the lyrics from the chorus of "Work it", provided as a service to the internet.