Seamus has always been causing explosions since first year. When you first met, he was too distracted by you, that he accidentally put in the wrong ingredient for a potion, and it exploded.

You and Seamus are now in potions and are assigned to do a [insert potion cuz I'm too lazy✌🏻] potion. You hand Seamus the ingredients and he puts them in.

Seamus accidently put too much of [ingredient🤩] and he knew an explosion was coming, so he hugged you as close as possible, covering you up so you won't get dirty or hurt.

As you would expect, it exploded, his face and clothes covered in soot. When it was over he looked at you to make sure you're okay, his Irish accent becoming very visible.

"You 'aight? I think I added double the amount then was needed.."