Hogwarts: Harry Potter's Return from the Witcher World - Chapter 345: Snape Doesn’t Cut It

... arry, I don't recall assigning you detention."

"You performed excellently."

"How could a student like you possibly earn a detention?"

Harry began to explain, "Professor Slughorn, it's not the kind of detention you're thinking of. It's a new tradition at Hogwarts in recent years. Every professor gives 'detention' to students they deem exceptional."

"Though we call it detention, it's actually more like tutoring."

Slughorn looked skeptical. "Really?"

...