You had a huge crush on Sirius, and pretty darn well hid it.

One night, you were walking down the corridors when suddenly, someone pinned you up against the wall and kissed your neck. "Shh... Shh... Don't panic." The voice said in a seductive tone. It was Sirius Black, the 2nd Marauder. Your skin tingled when his lips touched your neck, and you almost squirmed.