Severus rolls his eyes a little, and doesn't tell him that he's lucky to get an offer the Dark Lord hadn't gotten... He shrugs a little. "I probably could have cut it down a bit," like Slughorn, is implied but not said, "but it's important work and I did want to do it right."
"You can certainly watch me cast it, but it's not all that much to look at. The amulets can be fairly pretty, I understand; you probably wouldn't want to wear one on your watch fob unless you were in a going into a pub to order milk mood." Going on smirking, he explains, "Ovid is, well, you know, Ovid. Quite a different kind of bedtime story."
"That was his personality, though, not his lycanthropy. He had a quite unusual approach to it, you know."
"All right," he replies, mystified, and, as they separate, commences giving Rus's tea very obvious dubious looks.
(gives a biscuit) As in black belt, you think? Thanks. (hugs)