Being My Sister for Daddy by Jamie Aisher
Series: Black Book Fantasies, Book 3.
Approx. 4,480 words.
Published on September 9, 2012.
A girly boy has kept his infatuation with his sister secret for so long, until the day Daddy catches him sniffing her panties. To his surprise, Daddy fantasizes about his daughter, too, and comes up with an unexpected way for them to both realize their fantasies. Daddy makes him dress up and pretend to be his sister.