You decide that just turning Luke in to a balloon would be boring. You have seen that already, you had it done to you. It wouldn't be very exciting to just do it again.
His warm hands tickle your surface as he continues to push and bellow at your soft unbreakable balloon wall holding him captive. You could easily do anything to him, inside you and at your mercy as he is. What would be fun? What would entertain you a while longer?
You suddenly realize exactly what you would like to do. It would be hilarious, and best of all it would probably keep you and several other people entertained for hours!
You focus your thoughts and concentrate a little...