Remus told Lily he loved Sirius and she told him to tell Sirius. She said she was sure that even if Sirius doesn't feel the same way, he won't laugh about him or anything. So he went over to talk to him. "Padfoot? I need to tell you something"
Sirius sat on the couch, looking at a motorcycle magazine. He looked up from the magazine and looked at Remus. "Sure Moony. What is it?" Remus took a couple of deep breathes and said "I love you." Sirius looked at Remus in surprise. Sirius loved Remus since the first time they met but never thought that Remus felt the same way.
When Remus told him he was a werewolf, he was so happy he trusted him enough to tell him. He didn't even tell James and Peter until Sirius made him, saying that they shouldn't keep secrets from one another.
Now they stood in the common room, all alone (everybody went to the library to study for the exams), looking into each other's eye. Sirius wanted to tell him that he loved him too, but he found that his throat was dry. They were silent for a couple of seconds until Remus said:
"I understand if you don't feel the same, I didn't think you would anyway….." Sirius didn't know what to do; he could only think about how good Remus looked with his brown hair in his eyes. Sirius, without realizing what he was doing, leaned in and kissed Remus right on the lips. It was a soft kiss, which he enjoyed deeply.
Remus was caught off guard and surprised by what Sirius had just done. Sirius pulled away but Remus caught him and pulled him onto him for another kiss, but a deeper one. They went up to their dorm and made out until everyone came back.