"Hurrying, mate. Hurrying as fast as I can hurry," Sirius muttered as he shoved Regulus toward the front door of 12 Grimmauld Place. He was sweating; he could feel it dripping down his back, beneath his robe. His breath was also shallow and slightly quickened.
He was well aware of the silvery eye of the moon glaring down at them from above. He was more than aware of what this must be doing to Remus. This couldn't be good for him, holding it inside like this. And he was also more than a little anxious about getting into the house without blowing up. He wouldn't put anything past his mother; even with his useless, whining, sniveling little brother here to open the door.
And, perhaps on top of everything else, he was absolutely terrified of setting foot into 12 Grimmauld Place ever again. He held Regulus by the nape of the neck and fought the urge to slam his face into the door. He jabbed his wand into the side of his little brother's neck. "Unlock the door."
"Sirius," Regulus whined in reply. And while Sirius felt most of his terror on the inside (something he had finally managed to learn after that final, fateful night as a Black), Regulus was shaking like a leaf as he fumbled with an ancient looking ring of keys. "Sirius, she'll kill me. You can't do this to me! She's going to know I let you in, and she's going to kill me!"
"Then you should have thought of that before you bloody told her I was shagging James Potter!" Sirius wanted to smash his pinched, ugly little face against the door knocker. Boom, boom, boom. Until his face broke, until it was a mess of pulp and bone. But he could practically feel Remus behind him, and it made the hairs on the back of his neck stand up. "Open the goddamn door!" he hissed, only it came out as more of a bark. "Now!" And this time he did slam Regulus' face against the door.
Of course, Regulus screamed like a banshee as his face cracked against the metal knocker. Sirius highly doubted their mother would come running; what would she care who died on her doorstep, as long as no impure blood crossed the threshold.