Miley Cyrus stripped down to her undies in a new Tik Tok video. The 26-year-old singer/songwriter flaunted her slim figure in a black lacy bra and a pair of silk boy shorts as she danced with her 22-year-old boyfriend Cody Simpson. The blonde stunner and her Aussie beau showed off their coordinated moves, grooving to Ashnikko's catchy song called "Stupid". The video, that saw Cody dressed in all-black as well, seemed to be taken in the bathroom