Sirius laughed when James tossed tinsel at him, and he returned fire with a flick of his wand, sending a garland to twine around James' arm. Right, he should have known this wasn't going to end well.
"Really. Maybe we should take you to St Mungo's, have you checked out. I mean, modest tree grower is not ... the James Potter I know and love," he countered, grey eyes gleaming wickedly.
Moving back a bit, he spared a glance to the tree before scooping up some of the tinsel, tossing it toward James with a soft, barking laugh.