Harry and Severus became a couple after that day. They had agreed not to become intimate for a while because Harry was still at school, despite there being no rules because a simple Veritaserum could see if there was any coercion or preferential treatment. They spent some nights and most weekends together, talking, reading or simply brewing potions together. Of course they also plotted their revenge on Draco and Ginny. After much debating Harry and Severus had finally decided on an appropriate method of revenge on the other Gryffindor/Slytherin couple. A quick word with Dobby on Harry's part and a quick potion on Severus' and then were set.
The last day of term before the Christmas holidays was the date set for their plan. The new couple discreetly watched their prey. The change occurred automatically. Draco, tasted the potion but it was too late, he just looked at his godfather in horror. Snape grinned evilly at him and he gulped. A few seconds later Ginny spoke to Harry, only it was Draco's voice and it came out of Draco's head. The Gryffindor girl looked down at herself and screamed.
The whole school burst out laughing at such a girly scream coming from Draco Malfoy. At the sound of his own voice Draco, in Ginny's body, turned to look at his girlfriend.
"I guess they've finally got their revenge, Gin." He commented dryly once she stopped screaming. "How long does this last?" He asked Harry cautiously.
The only reply he received was an evil smirk.