She finds her authority challenged

I opened the cabinet again and took out some lube. I lubricated my ring and middle fingers and looked at my naked bent over twin from behind. Her thick bottom reminded how cute mine must be without actually having to see it and her clean shaven pussy lips looked very tight. I couldn’t help but imagine myself in the same position though it would be a little different: I kept a landing strip on mine because I was allowed to decide how I wanted to shave my pubic hair whereas I got to decide hers.

After I made sure my fingers were well lubed I looked back at her and felt a little bad about what I had to do even though I did it every day except weekends. She was almost shaking which she couldn’t control but she was quiet which she could control. She certainly was improving though I couldn’t expect it all at once.

I wished I could think of something to say to make these next steps less humiliating for her but despite a couple months of practice I still hadn’t thought of anything. Hopefully her desire to avoid this type of treatment would make it unnecessary eventually but until my mom told me to stop I would keep doing it.

I placed my left hand on the small of her nude back and she took a deep breath as I felt my panties moisten. I placed my fingers on her slit and she I watched her legs twitch and toes curl. I smirked as I reached my fingers gently inside her very slowly.

When I gave her first cavity search without practice she would moan a bit and get very defensive about not being aroused which led to her acting out. Since then I’ve been better at going slow enough she doesn’t moan as much unless I want her to. She squirmed a bit as I explored her pussy with my fingers. I took my time to try to not arouse her too much but then I got some lip.

“Are you almost done?” She sounded more upset than angry but it still was a challenge to my authority and I had to treat it as such.

I kept feeling around not yet satisfied though it was obvious she didn’t have anything in there.

“I can speed up for you.” I said as I moved my fingers up and down faster while pumping them in and out and she began to moan and covered her mouth in humiliation. I kept going for a while and I felt her pussy loosen as well as wetness that wasn’t just from the lube. She moaned again through her hands and I felt her tense up and her vagina start to contract around my fingers. I’ve never made my sister cum before but I have to imagine that would humiliate her most of all and I was afraid I wouldn’t be able to stop myself.

“I’m sorry, I’m sorry... I’m sorry...” she said as she tried to hold in the moans.

I had to remind myself I was fingering another person and not getting a third person view of myself getting fingered. I slowed down and gently pulled my fingers out of her as her lips were now partially parted with some juices leaking out of them and she groaned in frustration. Despite the fact it was likely horribly degrading she likely would’ve came if I kept going and was close enough to have it almost have been worth it. I decided to tease her just to see how she’d react.

“Did you not want me to stop?”

I knew even asking this would embarrass her and I hate having to treat her in such a way but she needs to be more compliant... not that I don’t enjoy the feeling of power it gives me at least a tiny bit.

“No...o...”

I watched her quim quiver and knew she was lying so I had to test her. Nothing but complete honesty would be acceptable. That’s how I’d want it for myself though I’d deny it a few times at first just to build it up and make the whole experience last longer.

“Are you sure?” I asked as I dragged my fingers over the length of her slit from top to bottom before pressing and rubbing against her clit. She let out a deep moan and covered her mouth again. She sobbed as I slowed but moaned again as I sped back up rubbing up and down her slit with my fingers while pressing my palm into her clit.

“Lac...cy.... I’m.... gonna.... c-c-c....um...”

We were making progress apparently. I dipped my fingers back inside her and they pushed in easily and she moaned her loudest moan thus far. I felt her push back against my fingers as she couldn’t control herself. She was giving into her desires, acting like the slut I am in my darkest dreams.

“That doesn’t answer my question.”

She paused as her whole body tensed. Her toes curled as I pushed deeper while moving my fingers up and down rapidly.

“... st-st-op.... ple-ease... La—Lacy... I-I don’t wanna cum” she screamed in between moans.

I didn’t expect her to have the self control to ask me to stop but I was proud of her for being able to still do so this close. I would’ve loved to finish her off but it didn’t seem fair when she was reaching the goals I had set for her.

I slowly removed my fingers as I watched her vaginal lips still spasming and her erect clit begging for more touch. Juices were flowing down her legs. She had a full body blush and was obviously very embarrassed by her body’s reaction. The whole room smelled like pussy and she was starting to sweat.

“Thank you for being honest with me, Lucy. I’m here to help you and I need you to trust me with the truth at all times as long as you treat me with the proper respect.”

She returned to gripping the dresser and was still breathing pretty heavily. She laid the top half of her body down on the dresser as she was near exhausted. I rubbed her back trying to comfort her and waited for her to respond which took a couple minutes.

“If... if I’m honest and respectful will... will this ever stop?”

I cooed at her softly and rubbed her back lower getting closer to her ass.

“I’m sure once mom sees how much better you’re being she’ll slowly ease up. I know how hard this is for you but mom and I love you very much and are just trying to teach you a lesson. If you’re meek and compliant like mom wants you won’t have anything more to learn.”

Her pussy seemed to be calming down as her breathing slowed.

“Lacy, it’s been two months and I’ve never been caught with anything but I’m kept naked, cavity searched, sometimes spanked, and I have no privacy and have to do all the housework. What more are you looking for?” She asked with her voicing shaking the whole time.

“Sure that’s part of it, but you need to treat us with respect at all times. No questioning anything I do or say. Prove to me you can do that and I’ll try talking to mom. I’ll see if we can maybe get you some extra privileges.”

She nodded.

“It’s time for the next part of your search. Show me how well behaved you can be.”

She sobbed a little but nodded again.