The first time they met, Sirius and James didn't recognize each other. That was probably for the best.
If James had looked closer he would've recognized the silver grey eyes his father was always complaining about, the eyes Sirius shared with his father. In the same way Sirius might have noticed James' untidy hair as his father always told him how unprofessional the same hair made Mr. Potter look.
Neither noticed.
Instead, James saw how Sirius' eyes sparkled mischievous and Sirius noticed how James always ruffled his hair as if he'd just gotten of a broom. They became instant friends.
The first time they hugged each other was two years later and by mere chance.
They'd just found out that their friend and fellow marauder, innocent little Remus, was a werewolf. Ecstatic for being sneakily talented enough to find out, they shared a hug of victory when Remus finally told them the truth.
This was also the first time that James noticed how nice his friend's hair smelled, a mix between peppermint and fire. It was a combination that was so Sirius that it made James smile in recognition and wonder.
He'd never smelt anything better than that. Sirius' smell.
Their first fight was terrible.
Sirius betrayed them, all of them but especially Remus and James couldn't just forgive him; wouldn't just forgive him. It hurt too badly and though Sirius asked for his forgiveness again and again he wouldn't give it to him.
Not until he saw Sirius cry. That was a first time, too, and was a heartbreaking sight. He wasn't a pretty cryer with eyes red, puff; miserable and his best friend didn't know what else to do. It had been five months since the accident when Sirius knew he loved James; was in love with him.
James' first kiss wasn't with Sirius.
His first kiss was with Lily Evans in a drunken state. Fourth year; James was drunk and stupid, Lily drunk and jealous. It wasn't love or even close and when they woke up the next morning both regretted it. She went back to her longing for someone she thought would never notice her and he went back to not knowing.
Not knowing what he wanted. Not knowing who he loved. Not knowing why he suddenly felt butterflies in his stomach each time his best friend's hand brushed against his. Not knowing anything at all.
Sirius' first kiss wasn't with James, either.
His first kiss, however, was extremely romantic; or so he thought at the moment. It was the day of new moon and he was sitting outside the castle with innocent, little Remus. They were talking about how the latter felt about being a werewolf and the former about his terrible family.
Before either of them knew some cliché words of worth were exchanged and so was a kiss. They were both thirteen.
One week later Remus confessed that he was in love with some Ravenclaw-guy. Like James, Sirius was only very confused.
Sirius knew he was in love with James after their fight. James knew he loved Sirius almost a year later.
It was the second week of Christmas holidays and James was standing in the kitchen making dinner. His parents weren't home – some gathering – so he was utterly confused when someone knocked on the door.
"Padfoot..?"
"'m sorry, I didn' know wh're to go."
As Sirius passed out in James' hall, exhausted and broken, James realized what an idiot he'd been. He sat there on the floor, waiting for his best friend to wake up, wondering if he could've changed anything.
Their first kiss together – and thus the first in one way – was as confused as their love.
Sirius was still tired and sad and broken and James was still so angry so when their lips met there were no fireworks and the only red sign was the blood in a cut on Sirius' forehead. It wasn't romantic and didn't last for very long, but it was a start and when they sat in the couch that night James brushed his hand against Sirius just because he could and that was magical.
Their second kiss was like New Year's Eve. It was fireworks.