John saw the two girls having a snowball fight in the courtyard. He had been writing his name in the snow with his wand, his real wooden wand from Olivander's, when they started tossing snow balls at each other. John wasn't so uncouth as to actually piss on the ground. No, he made the snow yellow with a charm in the shape of his signature. It was much classier. And it stayed even past the next snowfall, when it would appear on top of the fresh snow.
He had the brilliant idea to charm some of the yellow snow into a ball and toss it at the two girls. They were pretty close, and it would be hilarious.
He charmed two snowballs and sent them flying toward Racheline and Sally with a slightly insane laugh that could be heard across the grounds.