Sirius tried to ignore the familiar twinge in his gut, instead looking up past the castle's gates in reminiscence. The memories were starting to creep up on him; luckily they were mostly good from his perspective, so he'd have something to take his mind off of other things. When Peter showed up with his excuses, he felt just a little of the weight lift.
Giving Peter a nod and a grin that felt a little forced, he thought about Remus's plan for a minute before loosening his hold on James, but keeping his arm lightly around his best friend. "Sneaking around is definitely our specialty. And I'm never one to turn down cuddles." He smirked in that smug way of his before finally releasing James. "Why don't we do a bit of both? Wormy can go ahead and scope things out, and Prongs 'n I can check things out in a different direction. Wormy can meet us up by the kitchen entrance and if everything's clear," he looked over at Peter with a tilt of his head, "you can come fetch Moony. We've still got to nick back our Map to do this right, so I reckon us two could head to Filch's office and search for it. That'll give Moony an edge if we can get it back."
What he left unspoken was his assumption that he'd break off from the group with James, as was usually what ended up happening. He might have been taking for granted how much James would be willing to go with him this time, though it wasn't even a concern in his mind.