I guess this is another gay fanfiction so if you are uncomfortable with this then I would discourage you to read on. Enjoy!
It was midnight and Hermione Granger was sneaking through the west corridors of Hogwarts. She prayed that filch wouldn't hear her else she would have hell to pay. Earlier that day, as she was sitting eating her pancakes for breakfast, she got a text from Ginny Weasley, Lavender Brown, Cho Chang and Hannah Abbot to meet at the prefects bathroom at midnight. She obliged. She turned around a corner stealthily and snaked into the bathroom. In a circle stood the girls and they had placed a cauldron and some ingredients in the middle of them.
"Hermione! You gave me quite a fright!" whispered Lavender, clutching her chest. Hermione chuckled and apologised.
"So what is all of this about?" asked Hermione.
"We had the most amazing idea ever! We are going to make a massive Wingardius Sexius potion and then sneak down to the ventilation room and pour it in the pipes, when the fans turn on in the morning, it will be spreading through Hogwarts like the plague!" explained Ginny excitedly.
Hermione nodded and knew what she had to do, Make Wingardius Sexius. She noticed that the girls had got her all of the ingredients so she could start right away.
"How long do you think it will take?" asked Cho.
"I can do it in precisely 15 minutes." replied Hermione confidently.
The girls all quietly giggled and gave each other high fives. Hermione got to work adding the ingredients: 1/2 litre of cupid saliva; a tablespoon of rapeseeds; two unicorn hairs, freshly plucked; a mermaid tongue; a teaspoon of love potion; and a rose from the Hogwarts grounds. She stirred the mixture around for a few minutes and adjusted the heat. As she predicted, the potion was done in 15 minutes and was ready to use. The girls clapped.
Quickly, they poured the potion into a big jug and packed everything up. Hannah pulled up a loose floorboard and concealed their equipment in there. Then they all hastily left and headed towards the ventilation room, preparing to pour the liquid into the pipes.
They arrived at the destination, unlocked the door and headed in. The room was only small but it consisted of controls and wires. In the right corner was a small vent, that lead to every other vent in the castle .
"Bingo!" exclaimed Hannah.
They creeped over to the vent and prised it open slowly and carefully. Cho got the jug and opened the lid cautiously, pink steam rose from it instantly. The girls stared at it in awe.
"Here goes nothing." whispered Cho nervously.
She poured the potion into the vent and closed the lid. The girls looked at each other, not really contemplating what they had done. Then they burst into fits of giggles, which echoed around the ventilation room and into the corridor.
"Shit!" said Lavender. Filch had to of heard that. Cho quickly shoved the jug that used to contain the potion behind one of the many control panels. The girls were frozen still as they heard Filch stalk past the miniscule room. They all held their breath.
"Its alright sweet. We'll find those students who are out of bed." said Filch to Mrs Norris, reassuringly.
They had got away with it! They sighed in relief and started to sneak back to their dorms. Once they got to the main staircases, Cho headed up and to the right, to the ravenclaw common room and Hannah went downwards towards the Hufflepuff common room. The others headed up to the fat lady painting and muttered the password, "Red Rubies." The fat lady allowed them to enter. They all collapsed into bed and burst into unstoppable laughter. What an evening!