o12a12 - A way to scream when you finish a song perfectly. It’s like

A way to scream when you finish a song perfectly. It’s like a holy celebration. Or a total rage if you’re angry.

I got an All Perfect and I screamed ‘O12A12’ so loud my neighbors heard me.

I failed the song and yelled ‘O12A12’ like I was mad at the game.

I got an All Perfect and it was the best day ever.