It was impossible not to return Roger's smile, not when the other man was so enthusiastic, and Marcus felt a hint of a grin tug at the corners of his own mouth. It died slightly as the other man expounded on the possibilities of the kind of date he was avoiding, and he had to wonder if that was what it was like for all his teammates, a thought that made him glad he'd long ago decided that any sort of romance was more trouble than it was worth.
"Don't mention it," he replied with a small hand gesture, because really, it wasn't any trouble on his part. It wasn't as though spending time with Roger was a hardship in anyway.
Marcus flushed very lightly at the comment about learning anything about Muggles - it had been one of those throwaway things he'd mentioned offhand exactly once, and he was once again surprised that Roger had remembered. A part of him hoped that no one had overheard their conversation, because that was something he didn't need getting back to, say, his mother. Merlin, the woman would skin him alive, possibly literally.
Chuckling again as Roger continued, he tried to ignore the way his heart skipped a beat at hearing him say I love you, since it was so obviously a joke. "I'll never tell," he said instead of anything else.