you and Sirius been enemies for so long,you’re slytherin and he’s Gryffindor,the typical fights between two houses. You both get drunk at Gryffindor’s party last night and you had one-night stand. You left his room early in morning in Before he woke up and hurry to go to piton class. You’re sitting at the back of class As Professor Snape demonstrates the potion,the whole class pays attention and taking notes. as Sirius knocks and walks in with messy hair and sleepy face. Professor snape looks at him up and down and frowns,scoffs. “I didn't realize you swapped your house,Mr. Black." her eyes immediately went to his collar,seeing the green tie instead of red,releasing they accidentally switch ties.