Cormac McLaggen
Hermione was miserable. Then again, she had been this way for weeks, ever since Ron had started going out with Lavender Brown and making her insanely jealous. To get back at him, she had agreed to go to Slughorn's Christmas party with a man he despised: Cormac McLaggen. Cormac was treating her like a trophy and not a date - there was no doubt that he was physically attracted to her, but that was not the love she was looking for.
After a dance, Cormac guided her over to the side of the room. He stared at her and his eyes became soft. "Hermione…" he said.
"What?" she asked, trying not to sound annoyed. Cormac just bent toward her. Hermione then saw the mistletoe above their heads that he must have seen ages ago (why else would he have brought them to this spot?), but it was too late. Cormac grabbed her by the waist and kissed her forcefully. Hermione squealed in protest and struggled. Finally, she broke free. Enraged, she slapped him hard across the face and ran into the crowd of dancers.
She had never done anything violent like that since punching Malfoy third year. Finally, she found a tapestry and hid behind it. But she was not alone. She jumped when she saw Harry behind there as well.
"Hermione? What are you doing?"
"Oh, I just left Cormac…under the mistletoe…" Hermione explained breathlessly. Satisfaction came to her as she thought how that would surely get back to Ron. "Oh no, here he comes!" she thought aloud as she saw Cormac making his way over. She heard a rustle as Harry ducked out from behind the tapestry, probably to avoid interacting at all with McLaggen. McLaggen appeared behind the tapestry and Hermione jumped. He was drunk as a skunk.
"C'mere hot stuff and give me a proper kiss," he warbled. He seized her roughly by the shoulders and kissed her hard again. His one hand moved to her waist while the other kept her head in place. Hermione wriggled for a moment before realizing it was no use. Then, she got an idea.
"Mmmm…" she moaned sensuously as she began to respond to the kiss. She pulled Cormac closer to her and she could feel his mouth turn upward in triumph against her own. Hermione again felt a wave of satisfaction. This was her own little way of getting back at Ron, the ultimate payback…even if her choice of kissing partner was a total arse.
As she kissed Cormac and let her body rub against his to distract him, Hermione reached behind his back. There! she could feel it, in his pocket. Expertly, she nicked Cormac's wand from out of his back jeans pocket, even while still snogging him, and raised it up. She pressed her mouth in further, deepening the kiss while she used nonverbal magic. A bolt of red light hit Cormac square in the head. He drooped unconsciously against her, out cold. Hermione pried her lips free of his in disgust, untangled herself from his embrace, and pushed his sagging form away before he fell on her. Cormac fell backwards onto the ground with a THUD! Hermione quickly found his half-empty goblet on the window ledge, and manipulated it into his hand, setting him up as passed-out drunk. Then, she took out her wand, cast Obliviate on him, returned Cormac's wand to his pocket, and stepped out from behind the tapestry. Even if getting back at Ron had felt good, she did not want word of her and Cormac's "romance" to get out, for anything in the world. Which is why she waited until she had left the party far behind before wiping her mouth over her sleeve.