R. Kelly

T-Pain seems compelled to appear on every major single from the summer of '07, so his guest spot here is no great surprise. The Tallahassee singer sounds less automated than usual; his voice is almost sweet, even if his lyrics are playfully (and typically) vulgar. Kels is on a different mission: exhausting every possible sexual pun. He knocks out a few here, and even manages to fit in a Jacko impression.