Help

I want to reread a manga but I don't remember the title. It's based on a school and a Guy1 was just walking around in the courtyard, but the other, Guy2 thought he was the one who gave him a love letter and going to confess. It was all a misunderstanding and in the end they had sex. But then Guy2 wants to look for him but can't remember him, so with the help of his friends he looked for him in the entire school... Can anyone know this tittle? Thank for the help.