You give D.C time to choose what he wanted you to do as you begin to get patient. You haven't really shown anyone at your schools your shapeshifting powers when you were growing up. The only one's who saw you shapeshift were your family, and the doctor your father sent you to when you were a kid.
D.C: Oh, I've finally decided.
T.V: So, what do you want me to do then?
D.C: If you're really a shapeshifter, could you maybe expand your butt a bit?
T.V: A butt expansion? That's dirty, but I can't deny it. Hang on a second.
To show your butt growing, you head to get up out of the chair you were sitting on, and show it to D.C, while standing up. You used your powers to expand your own butt, causing it to increase a size, without breaking off the panties you were wearing. Hopefully, the new butt size you have grown would impress D.C as you sat back down without breaking the panties you had on, which were the only piece of clothing you had on, beside your t-shirt, and socks.
D.C: Wow, that was hot.
T.V: Thanks, so what do you want me to do next?