You're trained and remade, and your sister is taught

You have to keep things quiet, of course. It wouldn't do to just tell people that their queen is resigning to become a whore and her illegitimate half-sister will be taking the throne. There'd be revolts as fast as the news could spread, and even if they didn't execute you or **** you back into power they'd definitely kill your sister. And that just won't do.

You keep to your normal schedule, as much as you can, though you slim down on duties that would take you outside the castle where you can. At first your excuse is that you're just feeling slightly under the weather, then that you've had some paperwork build up, and after that you're working on a secret project. Whatever it takes to keep suspicious eyes away. It helps that many of your excuses have an element of truth to them - you really did have a goodly amount of paperwork to tend to, for instance. As for the secret project... well, in a manner of speaking, that's just the truth.

The reality is that you and your sister are both remolding each other. Cecilia's lessons are actually fairly straightforward; the etiquette of being a maid is quite different from the etiquette of being nobility, but there is still that foundation of etiquette to build on. Most of your time is put to bringing your sister up to speed on the status of the kingdom, it's laws and treaties, and teaching her how to make wise decisions as best you can. And also referring to her as "Anne", so she would get used to reacting to it.

Your own training, however, is much more... interesting. You've already done much in the way of pleasuring yourself with toys, but now your sister is using them to teach you how to pleasure another. How to tighten your holes, the best way to suck a cock, the noises a partner would appreciate most. A part of you wonders why she knows all of this, where she learned it, but the one time you think to ask she simply tells you not to worry about it. She also procures a number of potions, ones that will ensure your holes are always tight, ones that will keep yourself lubricated at all times, ones that muddle your perceptions of pain and pleasure - the last she tests the effectiveness of by slapping your bare tits. She deems that it has been effective once you moan instead of yelp.

Much of this training is a haze of pleasure, concentration, and memorization for you, much as you enjoy it. One part that still stands out in your mind, however, was the day Cecilia started you on learning to properly pleasure a woman. She had lifted her skirts, revealing herself to be bare underneath, and said "Come here, sister." You had swallowed, naked and nervous and excited, and crawled over to her until you could kneel between her legs.

"Now," she instructed you, "place your mouth over my slit and begin to lick." You obeyed, pausing only for an exhale before covering your sister's pink folds with your lips. You traced them with your tongue and marveled at the unfamiliar taste. Your sister had brought a fluid with the taste of men's semen to you before, so you could acclimatize yourself to the taste, and there were some similarities with this - but many, many differences. You thought you liked this one a bit better, at least compared to when you started - by now, you liked the other flavor quite a bit.

From there Cecilia guided you through first gently running your tongue along her cunt to prepare her, pushing it inside her and there identifying the movements and places that best pleased her, the correct way to address her nub as it became erect without hurting it or neglecting the rest. It took long enough that you lost track of time, lost in a world that began and ended with the vagina pressed against your face, before she came. Your sister shuddered and groaned in pleasure as a clear fluid squirted into your mouth and spilled across the rest of your face. She pulled away, and you remained still while your sister caught her breath. You hadn't been told to clean yourself off yet, after all.

Eventually she turned her attention back to you and smiled, gently reaching out to you to run her fingers through your hair. "Good slut", she said, and you beamed.

It was only the first lesson in such matters you received from her. But it stuck more clearly in your mind than most.

Eventually, the day came. Your sister pronounced you ready, and you pronounced your sister ready. The plan could be set in motion.