You decide to try to test your powers a little more. With Tiffany away, you focus on her underwear. You have always fantasized about girls in diapers, so you imagine Tiffany's underwear becoming a diaper. While you focus on that, you also think about her mind changing. You change her mind so that diapers seem normal to you.
When she comes back, you are amazed that she is just wearing a t-shirt and a disposable diaper. Your jaw drops the floor when she seems okay wearing the diapers, and sits down. After she sits down, she grabs a blanket and covers her lower half. From the look of it she had goosebumps.
She sees your reaction and says, "What?"
"Uh...nothing sis."
Then...