You and Theodore were in the 5th year at hogwarts, both in Slytherin. Yet, you didn't get along at all. You were siblings with Tom and Mattheo Riddle, who were friends with Theodore.

Theodore was staying during the Christmas break and you had brought Pansy and Daphne, two of your friends, over to your house. Not knowing Theo was there.

When you were getting snacks before watching a film with Pansy and Daphne, you heard a guitar playing and checked to see who it was, and it was Theo.