Okay, In all seriousness, after I leave this comment, I am so re-reading this!
Three fingers and a handful of spunk will have to do or Severus will be in serious danger of climaxing prematurely himself and then he'd have to Obliviate the boy.
Best. Line. Ever! I mean, if I could see anyone actually doing this it would be Severus. And carSalesmen-Arrogant!Regulus, was just so new and, well, fun!
Surely some of Harry's parental figures will remain unsullied by sordid detail?
"Of course, my dear brother would never have stood for that," Regulus muses. "Kept the wolf on a very tight leash, I can tell you. Literally, I might add."
"So, how's Germany been, then?" Harry asks desperately.
This part made me die laughing. Poor Harry and his day of tainted images. xD Oh well, someone had to ruin his innocence eventually!