Although Sirius hadn't expected Regulus to jump away as if he had been attacked, which he hadn't, his wand had slipped out into his hand, by his side, just in case his brother was a little bit curse happy. It would have been interesting, anyway, just to see what spell first hit his brother's mouth to curse someone. But it was easier not having to deflect the curse, when that potentially could have hit either Reg or Remus for doing so.
But he couldn't keep the grin off his face. He was just so happy to be there, with them, and Reg was calling him a git. It was like old times, good old times. Reg was getting better though - fast on the draw and with enough self-control to recognize him and not attack. That was new. Sirius returned the large hug, his wand still in hand from being ready to defend himself. It was big and cozy and strong, but Sirius let go of it as soon as Reg did. That was one hug so far, and Sirius hoped to get at least one more before the night was done.
Returning his arm to Reg's shoulder, Sirius followed Reg along easily enough. Oh that sneaky bastard, Sirius thought merrily as he noticed what Remus was doing. Sirius gave him a conspiratorial wink and led the way in. "Maybe you could play here someday," Sirius suggested.