Love had always been a feeling Remus had for Sirius Black. It had started long ago when they were much younger. Sirius had instantly become his favorite person in the whole world. Somewhere along the way he'd felt that love transition into a romantic way and that had caused The Thing to exist between them. Remus knew he was in love, but that unfortunate understanding that formed between them of -- we know, but we're too scared of losing each other to try -- came into play.
The saddest part was that although he had known he was in love, Remus hadn't known quite how deeply his love ran until the Willow Incident that nearly destroyed their relationship entirely. Remus had forced himself to shut Sirius out of his life for a good while after that. And Merlin, it had been absolute misery. Loving Sirius as deeply as he did brought them back together, but that similar sort of misery came back ten fold during the war when everything went to hell and they were at each others throats on the rare instance they even saw each other. And then, of course, with Sirius in prison and no way for Remus to see him? Absolutely devastating. It was a horrible realization to have that feeling of such true, deep love and be reminded of it only to not be able to act on it.
That was why here, Remus wouldn't let his fears control him with his relationship with Sirius anymore. This was their chance to get it right, and they were doing it and he was so, so happy. As Sirius went to work with his pants, Remus did the same. He still felt shy but hell, he wasn't going to let that stop them. "I want the clothes forgotten on the floor," he said, a little growly.