Sirius wasn't even listing to what makes was raving on and on about. Peter had left for class five minutes ago but Remus or Him couldn't escape his angry clutches. Sirius made eye contact with Remus. Sirius walked over to remus and said one thing. "Closet at mid class."
Remus nodded understanding it but prongs got curious.
"What did you say sirius?" James tilted his head to the left.
"He told me that mcgonagall is going to give all three of us detention and that were going to blame you." Remus glared at prongs.

James sighed and let them leave for class. Sirius and Lupin walked side by side, thier hands brushing but neither pulled away from the contact with eachother. James headed to Transfiguration with Remus while Sirius went to muggle studies.
Remus was generally not bored. Especially not in transfiguration. But now all he could do was think about mid class...
Little did he know sirius was also thinking about thoes lines.
Sirius was learning about a thermos. It was kinda interesting but he kept drifting to what he was planning to do when mid class came.
Both classes drew on long. But finally after a seemingly forever amout of time, mid class came and the both of them were excited. And not just in the head.
Remus asked to go to the bathroom (mcgonagall permitted) at the same time Sirius did (He too got permission.)
They always met at the same closet. The one right by Charms. Remus got there first and slipped inside and prepared himself.
Sirius being farther away took him another minute or so to get to the Closet.he finally reached it and slipped inside of that.
Sirius caught his breath. And he met Moony's eyes.
They came to a silent agreement after staring for a second. Sirius leaned in and kissed Remus gently on the lips. Remus returned the kiss putting his arms around his neck. Remus also put his hands on sirius hips making sirius moaned slightly and Remus took the opportunity and slipped his tounge inside his mouth. Thier kisses got rougherand faster. They stayed in the Closet kissing for an unknown amount of time. They hastily got dressed and checked the time. They missed the rest of thier classed so they just walked back to the dorm to see a very worried James and Peter.
"WHERE HAVE YOU TWO-oh..OH" James ended with a laugh

And that folks is how James found out they were dating.