Regulus smiled at little, because he already had Remus' interest, and that was the only thing he needed. That and sex, obviously. "No, I'm telling you, because I don't want to fuck," he deadpanned. "I knew Gryffindors were thick, but I didn't think they were this bad."
He raised his eyes, meeting Remus', and while he knew that this was an act, the growl made him hornier, but he didn't give in just you, because this could be fun. "If you aren't interested, I don't see why I should sit here and wait. I don't consider 'getting away with something', but doing something that I want," he said, defiantly. They knew that he didn't matter but if fake jealous would get the result he wanted, he was more than happy to play along.