Remus gave a loud snort in response for several reasons. As he put his head on Sirius' shoulder, letting his arm drape over the boy's stomach, he looked up a little bit. "I'm shocked, but glad. I thought I'd never rub off on any of you. Can never tell whose more hardheaded either." For the most part he was only teasing, though it was kind of true in regards to James and Sirius. Thankfully, Remus still loved his best friends no matter what.
Part of him wanted to know, in return, what Sirius could like about him - if anything - but he couldn't bring himself to do it. Sirius wasn't the one who had been hiding feelings for months, so really he didn't expect much to be said anyway.