At the end of the lesson; it was hard to tell who was blushing more: Hermione, because she had never had a conversation like this with any adult; or Narcissa, because she wasn't expecting to have to discuss this practice with Harry and Hermione until they were at least in their 6th year. Then, Narcissa could pretend, in her mind at least, that they were adults, and not children. It just felt so wrong in discussing sexual issues with a child Hermione's age.