"You can't do it over because we have other projects," Regulus answered. "I think I know what's my work and what's yours, so don't worry about getting a grade you haven't earned." That was good ethics from Weasley's part, enough to prove that he'd make a lousy Slytherin. He should have tried to get a better grade because the potion was better.
"Then, you'll still have the pleasure of my company and my lessons," he answered.
Regulus didn't really understand why Weasley needed something else to focus on. He'd always had some purpose in life, something to concentrate on, from learning the Dark arts, to gaining entrance into the Death Eater, from receiving the mark to killing the Dark Lord. He'd always had a purpose, an aspiration. He didn't need for things to keep him busy. Weasley seemed to disagree, but Regulus wasn't sure he wanted to see the boy fail at making the potion, and failing he would. It was inevitable at first. "Fine, give me an essay, I want every step described, both in how the potion is supposed to look like, the ingredients necessary, why they are important. You skip anything, you'll write it again and again until I'm satisfied. You have two weeks for the first draft."