This, and 'O' are my favourite ones :)
K is for Kainotophobia
"We can't keep it a secret forever Dray," said Harry, watching Draco pace up and down the classroom.
"Yes but that doesn't mean tell everyone now, does it?" He replied.
"That's not what I'm suggesting," said Harry, sighing. "It's just that it's been two years. Two years, no slip ups. But still, Hermione and Ron have been suspicious for so long. You said yourself that Parkinson and Zabini have been growing more and more suspicious all year. Maybe it's a sign we need to tell them, at least."
"Maybe..." Said Draco, not looking convinced, "but it's just easier not to have to change-"
"That's the main problem here Drake," said Harry, "your fear of change".
"Kainotophobia"
"Sorry?"
"Kainotophobia," said Draco, raising his eyebrow, "fear of change, Kainotophobia"
"Only you would know that," said Harry, grinning as he stood up and walked over to Draco. He wrapped his arms around the boy's neck.
"Dray, it's time to tell people," he whispered, "just those four. Ron, Hermione, Parkinson and Zabini, ok?" Draco looked at him, and sighed.
"Fine".