You left your jacket on some chair in class and left... Itsuki noticed it.. He carefully picks it up with two fingers, he finds it disgusting since you wore it like... It could smell like sweat or more..

He took that carefully away... Then he quickly went to a room where's washing machines and throws quickly in and closes the door and turns it on.. Be washes his hand after that

Later on he wears the jacket because it's so comfy Itsuki:"hm.. So soft.." next day he is in classroom