Harry was still slightly surprised—on the Hogwarts Express, his trousers down to his ankles. Malfoy between his legs. He whined lightly as Malfoy's teeth scraped his sensitive skin before his tongue swirled around again; he started sucking.
They had to be careful. Even if they were under the Cloak, someone could still hear them. Malfoy didn't stop until Harry was spent and then Harry returned the favour.
When the train came to a stop, Malfoy had just finished. He got up, dressed himself and made his way out. "Welcome back to school, Potter."
What a difference a year made.