Twilight was going to be hers. Rarity was confident in that. Twilight wasn't particularly hard to read, and Rarity relished the attention dear Twilight lavished on her. The glances and leers. The blushes when she was complimented. The compliments Twilight gave her, which were full of so many unspoken feelings. Soon Rarity would have Twilight. She would lick her marehood whenever Rarity asked. She'd take Rarity's horn wherever Rarity wanted to put it. Twilight would be serving her and she would enjoy it. After all there was that submissive streak Princess Celestia had so kindly nurtured.
If Twilight was disobedient, she would receive lashes against the rear in accordance with her crime. It would pain Rarity to harm that lovely rear, nearly as much as it would arouse and thrill her. She'd be trained to obey all that Rarity commanded. To be Rarity's little slut. She wouldn't need her library when Rarity was done with her. Or her pet dragon. Or any other friends. All she would need is Rarity. Anything else would just be an example of Rarity's generosity.
Rarity didn't know why Twilight, in particular, filled her with such a madness. Such a selfish kind of lust. Rarity hadn't even known herself to be into other mares til Twilight had arrived. Slowly but surely though, Rarity's mind continued to move along such lustful and obsessive pathways. It wasn't Rarity's fault that Twilight was such a seductive little minx. Rarity had been bewitched, so the only thing she could do, was capture her and make her hers. Anything else was unthinkable.
Every night Rarity shuddered herself to orgasm through vigorous masturbation to these thoughts. She wanted to tell herself that this was just a fantasy. That these thoughts were harmless. That she could control herself through self-pleasure. But Rarity knew that every night she was getting closer and closer to needing this. One day it would come true. One day she wouldn't be able to stop herself.
Rarity could only hope that Twilight was into this stuff as much as she was.