In the spirit of “Sex Weed,†“Sex Kitchen,†and “Sex Planet,†R. Kelly’s new single, “Genius†(wouldn’t a better title be “Sex Geniusâ€?), travels straight back to the days of TP-2.com and TP.3 Reloaded. Kells went retro with 2010 and 2012’s Love Letter and Write Me Back, respectively, but just as promised, “Genius†does what its album title (Black Panties, out November 11) hints at: “Tonight, you’re lying with a sex genius.â€