Anyway, here's the fic.
Jensen and Jared are in high school together. They used to be best friends until apparently Jared found out that Jensen was gay and he wanted nothing to do with him. He picks on Jensen because of his sexuality, and Mackenzie and Megan hate Jared for what he puts Jensen through. But Jensen says it's okay, because he has the best boyfriend in the world and he makes everything else alright.
On the day of their high school graduation, Jensen has a surprise planned, and he starts singing some really cheesy pop song on the stage (I think it was 'When You're Looking Like that'). He's singing to Jared and their brothers and sisters are panicking, wondering how they're going to deal with the fallout. But it turns out that Jared is Jensen's boyfriend and they've just been hiding it because I think they didn't want to deal with Jensen's parents blaming Jensen for corrupting Jared - could be the other way around, Jared's parents blaming Jensen for turning their son gay.
The fic ended with Jensen and Jared driving off with Chris and Steve. Chad, Tom and Mike were also part of the fic.
EDIT: Found. Link in comments.