Timing wasn't really Peter's best attribute. And being back with his mum meant about twenty minutes of inspection before he could even leave the house - boy he missed Hogwarts. So it was unsurprising to him that he was the last to show at Remus'. He could already hear the unmistakable voices of his friends behind the door.
So he walked in, only pausing for a moment to consider whether he should have knocked first. But the door was open. "W-Who are we provoking now?" Peter asked, catching the tail end of the conversation. He stood and glanced at each of them, nervously smoothing his hair as he picked out a spot to sit in. "Sorry I'm late."