it was probably Nagisa's since Rei in the morning was getting dressed like that all eagerly.. irdk why Nagisa wouldn't have changed his clothes though xDD (▰˘◡˘▰)
I think Rei's and he just hadn't time to pick new clothes and maybe Nagisa slept till afternoon and hadn't time to jump to his house and change his clothes
Okay...I have a question. Whose house did they freaking sleep if they didn't have time to freaking change clothes??