Credited to Mick Jagger and Keith Richards, Ron Wood apparently wrote the song's main riff, a piece of music he took with him to Munich's Musicland Studios where he and other guitarists were auditioning for the second guitarist slot left open after the departure of Mick Taylor. For his contribution, Wood would receive an "inspiration by" credit on the final album. In 2003, Wood recounted, "All of us, independently and together, were into reggae, and it was also a mood of the time. I had this particular lick that I took into the studio and the others said, What are we going to start with? and I said, I've got this song. Charlie [Watts] was sitting behind his kit, so he was already into it and then Keith and Mick both got into the motion of it. That was 'Hey Negrita', which came together very easily. The key to getting a song across in this band is never to try and write all the words. If you've got the rhythm, you're lucky! Let Mick write the words and then you're in with a chance."

In his review, Bill Janovitz says, "[Hey Negrita] straddles Latin, reggae, and funk musical styles. Mick Jagger had been spending a lot of time in New York City and absorbing new elements of dance music, specifically Latin forms."Black and Blue is known for its heavy contribution from Stones recording and touring veteran Billy Preston, of which Janovitz says, "...Preston plays a very percussive Afro-Cuban-sounding piano part over the... riff." Also prominent is Ollie Brown (another veteran of the Stones' mid-1970s tours) who provides the song's heavily Latin-influenced percussion.

Of the song's substance, Janovitz says, "Jagger again chooses not to shy away from controversy... "Negrita," a Spanish term translating as "little black girl," was a pet name he had coined for his wife at the time, Bianca, a Latina. The song, however, is undeniably sexy, and Jagger is playing with the stereotypical Central and South American approaches to the battle of the sexes."

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Wikipedia