You use your powers to pull down her swimsuit a second time. She's still smiling, but she's also starting to get a little annoyed with you.
"Will you stop that?" she says in a half playful tone, snatching the lamp from your hands, "I wish you knew what it was like to have someone staring at your ass all the time."
Her comment activates the magic of the lamp, and you feel your clothes begin to rip away as your ass expands into a cute black bikini and the rest of your body transforms into that of a sexy woman.