You and Draco were in potions class, and while the professor was talking, he chose Draco

"Mr. Malfoy, come forward and tell us what your love smells like"

Draco snorted, stepped forward and said in a quiet, serious voice

"I feel... Coffee. perfume and..."

He sniffed, and you realized that his love smells like you when you two hate each other, presumably

"Lavender..."