Harry Potter and the Imperius Curse.

Harry stormed into the hallway near the entrance to the common room, firing sparks at nothing and cursing at anything and everything. Detention with Snape was never a pleasant experience.
“Dilligrout!” he half-shouted.
“Alright. Alright,” and the portrait swung open and he climbed through.
Entering the room, he saw that the fire had burned out and everyone had already headed to bed, all except Hermione who was sprawled across a chair by the fire lying with her head resting on the arm, nestled in a pile of library books. Smiling, Harry walked over and went to wake her up, but he stopped, noticing what she was reading:

“Illegal magic is often hard to trace, especially within the grounds of highly protected magical establishments like Hogwarts. The scheme to trace magic became so expensive, that the responsibility to police spell casting was left to teachers and hired ministry officials that…”

He threw that book aside, losing interest and then froze, noticing what was under it. Hermione was dressed in her usual Hogwarts Gryffindor uniform; red and gold tie; white blouse; a black jumper with the Gryffindor colours across the neck; a black skirt and long black socks with small black shoes; but that wasn’t what had caught his eye. Her skirt had ridden up, along with her white panties, and they were now pressed firmly against her tight developing cunt.
Harry had an idea then. Thrusting his hand into his robe pocket, he pulled out his wand and began to rub the tip in between her pussy lips. It wasn’t long until a small patch if wetness was seeping through the thin cotton and Hermione was stirring and moaning softly in the armchair. Clutching his wand, he pulled away and stood, staring down at her wet panties.
“Imperio!”
Hermione rose, almost puppet like, staring at Harry with a kind of bored yet excited expression.