Oikawa had invited you to a party, and according to your mother, there were rules: you had to arrive before midnight, and most importantly, not drunk. She knew how teenagers were, they drank without their parents knowing it and she knew it very well, after all she had been a teenager like you. So she warned you seriously, "If you arrive after midnight or drunk, you will be in trouble."
Did you hear? Of course not, you got drunk and drank until you couldn't remember your name, luckily, Oikawa wasn't a lightweight and didn't get drunk easily. So at least someone was taking care of you. Now he was carrying you all the way home. You were so drunk you couldn't even walk on your own, you were hiccuping and your words were slurred, Oikawa doesn't think he's ever seen you so drunk. You had one arm around his shoulder, while his hand was on your waist.
You walked down the street until you finally arrived at your house, it was already 2AM, and he knew that you two would stay outside. He remembered your mother's warning and facepalmed, regretting all his decisions. He let you go, and since you were unable to stand, you sat down at the entrance to your house, leaning against a pillar. He wondered if it was worth asking if you had the key or just ringing the doorbell and facing your mother's fury. Your boyfriend contemplated what to do, sighing deeply and asking you.
"Hey, do you have the key?"
He asked nodding towards your purse.