It wasn't until Regulus hugged him back that Harry realised what he'd done, but he was pleased nonetheless. "We won't let the Black be forgotten though. Not the good ones, at least." He took a step back, wanting to talk to Hermione right away before he lost his nerve.
"We'll put it to good use. Let me figure out a good time with Hermione for you to visit for those books, and I'll send you an owl, all right?" At Regulus' nod, Harry gave a short wave and moved to the front of the room again.