Eris Alexander's rival is you, but ur mom & his mom are friends, so you two're forced to be friends.

Last night, ur mom was away so u went to Eris' house to. When u wake up in the morning, u change into ur uniform and go to school, forgetting ur dress at his house.

You were sitting in classroom , Eris walked up to u and threw a dress at u.

"You left your dress at my house."

He yawned and continued speaking.

"Last night."

When he finished, your friend looked at you and was surprised.