Friend gave prompt: "If you do that again, I'll throw you out that [stupid] window you...
"If you do that again, I'll throw you out that [stupid] window you - what are you doing?"
"Checking how high the drop is, see if it's worth it."
"You do know you're not supposed to jump out by yourself?, right?" he asked, puzzled by her usual nerve-racking carefree attitude.
She didn't answer and instead, opened the pencil case she was holding again - his pencil case, and prepared to throw another pencil out the window. This time, it was a 6B Faber Castell super high-grade and expensive pencil.
"No! Please don't toss it out!" he breathed, terrorized. He could bear with a simple kind of stolen HB pencil shattering down the school's courtyard, but this Faber Castell... he wasn't letting it go.
Before he could understand what he'd been doing, he was having the criminal pencil-thrower pinned to the ground under him, holding tightly onto his pencil case. They both looked quite embarrassed and bewildered by the turn events had taken, and it wasn't long before the 'whoops' atmosphere was broken by a childish act, namely our dear pencil case owner grabbing his belongings back. He then tried to get back up, but the girl held onto him, and the pair went beet red. As soon as she let him go, he was running out the classroom like some terrified rabbit.
She got up on her own, muttering something like "Maybe I just should've jumped out the window while I could..." and banged her head against the window three times.
Note: in original prompt, f word instead of 'stupid'