Remus knocked once, twice, twice again. The pattern they did on the dorm door each time they entered, he’d never been able to break that habit. James had made it up in first year. There was no real reason, just because he thought it was "wicked’. Remus remembers it as if it was yesterday, the bright eyed boy with the messy hair and the crooked glasses, grinning up at them like it was the most brilliant thing anyone had ever thought of. Sirius doesn’t remember it at all.