It's the same interlude she was talking about in her recent interview with 'V' magazine. Weed is disgusting, but Rihanna makes it sound so rousing!
The music is chilled and soulful with jazzy undertones, and her vocals are smooth and very sensual. Nice cut. Sadly... it's just an interlude...
ETA: James Fauntleroy is taking credit for the song, which explains why his name is in the title!
Alternatively, listen here.