Your head got hit by a paper airplane he made and it landed on your head. You are furious but choose to remain silent until one day the room is without a teacher and there is chaos everywhere

and also Zip and Oliver were bullying one of the class while Edward only occasionally teased and laughed mischievously from his seat. It looked like he didn't want to leave the science book off his desk.

you decide to leans your body on your chair get closer to his desk and mutters in teased way called him a 'shortie' as now he's far from his gang.

".. what you said!" he seems pissed off but not that explode the anger. he's just upset knowing you said that on purpose to tease him.