I've never gone in depth with his character, like Teruteru, so this might be bit short. So, Fuyu is a bit of a tsundere in this and Peko is just his friend, she isn't his "tool" or anything.
You were infamously known for being friends with Fuyuhiko. Because no one fucked with him, no one fucked with you. However, unlike him, you were the exact opposite. You were shy but bubbly. You never raised your voice when you were angry. As of now, you were waiting for Fuyuhiko to get his stuff so you both can leave the school. You forgot your umbrella but you didn't really care. You loved rain! Fuyuhiko trudged over to where you were perched and stared at you.
"No umbrella, Y/n? Again?"
"Why would I need one? I love rain!"
Fuyu sighs.
"Whatever, let's get going."
You both walked with each other out the gates of the school. You both walked together because you lived next door to each other. You were skipping next to him and he pointed out the puddle a few feet away to you.
"Oi, loser. You'll get me all muddy! Stop skipping!"
You pouted, but didn't listen. It was amusing to you. You stomped harsher and continued to skip.
"Dude!"
You looked over at him and before you could open your mouth to respond with a snarky remark, your foot slipped from the muddy, watery mess that collected in the sinkhole. You fell and your head collided with the concrete, knocking you unconscious. Fuyuhiko laughed and thought you were faking it but after 3 minutes and a few weird glances, he knew you weren't and picked you up. He thought that he'd take you to his house because it was closest and you were his friend.
When you awoke, you were in Fuyuhiko's room, specifically in his bed. Your clothes were different as well. It wasn't your school uniform. In fact, they were your clothes you put on your bed before leaving to school. You giggled and almost on cue, Fuyuhiko came into the room, holding an ice pack. He lifted your head and put the ice pack beneath your head like a pillow. You sat up and held the ice pack to your head.
"Idiot, you fell. I brought you to my house just so I know you don't die."
"So, we're friends."
"Sure..."
"Yay!"
"Maybe we could be more?"
"What, Fuyu?"
"NOTHING!"
He forcefully shoved you back down and put the ice pack in its original soot. He blushed and looked away, audibly huffing.
"Hey, Fuyu?"
You gripped his sleeve to get his attention and tilted your head.
"Yeah?"
"Can I stay here for the night?"
"... Whatever..."
"Yay!"
You pulled him into a hug and he reluctantly patted your back awkwardly. He pulled away and asked if you wanted to watch a movie. You nodded and he pulled up Netflix, chose a movie, and dimmed the lights. After an hour or so, you fell asleep on Fuyuhiko's shoulder. He slowly grabbed a blanket, covered you both, and kissed your forehead. Hr smiled down at your sleeping form, or what he presumed sleeping. You looked up, winked, and kissed his cheek. Then, you nuzzled back into his chest. He grabbed your chin, made you face him, kissed you on the lips, then let go.
"Be my girlfriend?"
You kissed his chin.
"I'll take that as a yeah."