Sirius had been waiting for Remus all day, so when the door opened revealing his friend he immediately jumped to his feet and darted over to the other man. Allowing the collar to be put around his neck, he waited before he jumped up to plant his front paws on Remus' chest and lick his face with a happy bark.
However, when Remus began to lead him out of the room, Sirius protested, growling at Remus. After a moment, he began tugging on the sleeve of Remus' uniform with his teeth with another low, vicious growl before sitting on his haunches and looking up at him. Tilting his head to the side, a continuous rumble sounded from his chest as he sat there. He did not want to go out with Remus in that uniform. Sirius hated that uniform.