You Make My Dreams by Hall and Oates.
It was Valentine's Day. The castle was almost empty, and a boy and a werewolf were dancing a laughing mock waltz under the serenely snowing ceiling of the Great Hall. In the middle of a drawn-out twirl, Remus stopped to pull Sirius closer by his collar.
"You make my dreams come true," he whispered. And if the other boy thought it was cheesy, he masked it well as they kissed giddily.