Severus rang up the book, smirking when he read the title. For the Relief of Unbearable Urges. With those splotches on the cover, it required no comment, he thought, slipping the receipt and a message between the pages of the book.
Lol, leave it to Severus to make an educated guess and half-foul it up.
I love how you weaved in the past--the people that Harry left behind, that come back to bite him on the ass. I'm not usually for whodunits, but this was very nicely done. Bravo!