Potter&Black - Head Cannon

When James and Sirius met, they were instant friends.
Nothing ever came between them over the years...
Except for Lily Evans.
James couldn't help but act a certain way when he was around her. Even when he tried, his words were arrogant and taunting.
Sirius on the other hand, was laid back and quick witted when it came to Lily, and was fast to become good friends with her. James was beginning to notice this, and he did the only thing he could do.
Pulling Sirius aside, and out of ear shot of Remus and Peter he whispered:
"You know how I talk about Lily? How I talk a big game.."
"Yeah..?" Said Sirius, almost intrigued.
"It's more then just some crush. I like her. I have this thing in my head...this picture. I wanna' be with her Black." James said hurriedly.
"Then be with her! But stop acting like a prick. One last thing though..If it doesn't work out, I call dibs, and you can't hate me for it! Sirius laughed.
"Deal." James grinned.

It all worked in James favor over the next few years.
Sirius watched from the sidelines, truly happy for his friends, even though apart of him wished that Lily had turned him down just one last time.