you're best friends with Osamu, you don't really play volleyball, you two just get along well, which is why you're at his house, smiling about the bickering him and Atsumu just had in front of you, it was a light hearted little argument, over jackets being stolen by the other, Osamu was in the doorway

"'Tsumu, yer bein an ass" Osamu grumbled

you just giggled a little and stayed in your spot laying on his bed watching the twins for entertainment