It started as a joke, but when Ron took that picture of Draco using the loo he didn't expect this. It was after a double potions class. When Collin used the potion on the photo Ron totally expected the image of Draco to run and hide off the side, but it didn't. In fact it began doing more and more illicit things the longer he stared. He had to find out if Draco was really like that. That's how he ended up in the small cubicle in the dungeon with Draco plastered to the wall, his lips devouring the blonde's in a wanton kiss.