Kate to Ruin My Life

I stared at the door for a split second before shockingly realizing it wasn't locked. I moaned as I pulled the massive dildo out of me entirely and chucked it towards the closet. Standing naked in my room is better than nothing I guess.

"That was your warning." Kate remarked as she kicked the door wide and waltzed in. Her body was as fit as ever, decked out in her usual workout outfit. Sweat glistened on her skin from her morning run. Her perfect tits showed through her sports bra. The largest difference that I could see between the sister I knew was a massive bulge in the front of her yoga pants. She paused and stared at my naked body and erect cock. "You jerking it?" She questioned. "What? Is Trish not putting out?"

"Umm... no, we're fucking." I stammered.

She sauntered forward with a quizzical look and put a hand on my cock as if to inspect it. "Why is it not getting bigger, Chancey? You're making her cum on it, right?"

"Yeah," I say gripping her wrist and pulling her hand off of my cock. I knew why. "She's making me wear condoms when we fuck. She's still kind of old fashioned."

"No, no, no, Chancey. That ain't a good squeeze if she won't fuck you right." Kate pulls her cock out of her waistband and stretches it out next to yours. "See? Mine is as long as yours and I'm not even erect. Ellie even lets me cum inside her... I trained her so well." She starts to jerk her cock as she talks and I watch it grow incredibly quick before me. "When we get going Ellie might cum 3-4 times before I blow my load. I swear, I might get her pregnant and make her my Beta Bitch. If you want to do that, you've got to learn my moves." As she finishes her diatribe, she has stroked her cock to a size dwarfing mine in both length and girth. She pulls her foreskin back and presses her cock against mine. "I mean, come on, Chance!"

"I guess so..." I say, somewhat turned on by Kate's pheromones and the feeling of her cock against mine.

"I can show you how." She says with a grin as she squeezes my cheek.

"Would you?" I say, hopeful Kate can help me grow my cock.

"Sure." She strolls behind me nonchalantly and then quickly before I can stop her, she locks my arms in a nelson hold. This is exactly the shit she _would _pull. I struggle wildly as her pulsing cock presses into my back. "Chancey, you just have to get a little rough with her. Show her who is boss." She talks through gritted teeth, but her arms are like a metal vice. She lifts me of the ground with her massive muscles, leaning back to allow her cock to scrape down my back until it is pressing against my asshole and then as she shifts her body, it is sliding across my vagina.

"Kate, stop!" I say, flailing my limbs uselessly.

"You just have to show her what she is missing..." She ignored by protests and started to push her erect cock head into my pussy. Her foreskin pulled back and pre-cum smeared against my pussy lips as the she **** her way in. My body started to tense and my cock pulsed as she easily filled my wet pussy with just the tip of her cock.

"Aaaagh! Fucking stop, now!"

"...And she will beg for your cock." She pushed her way even further and I could feel my walls start to fade. It felt so good to be filled by my sister. My empty pussy felt so hungry after the sudden excavation of the dildo. Plus, the feeling of her warm, cum-dripping cock felt much better than the dildo. Now that she was inside me, all that was keeping the rest of her cock from slipping inside was my own arms holding my body up in the air. I could simply release and let her plunge all the way inside of me.

Memories flooded back. We'd done it before, plenty of times. On slow weekends, mom would give us condoms and we would practice, learning the skills that we would put to use. Getting fucked was natural, but being really good at fucking someone else took lots of practice. So we would pair up and try positions, mom would supervise to make sure that we were all treated well by each other. I was last to join these sessions, but once I was of age I caught up quick. After a time, mom felt we could be responsible and let us fuck on our own. Kate always had a big cock and I'd always loved the way she felt inside of me, but the last time we'd fucked she came inside my pussy and wouldn't return the favor. That might fly with your partner, but this was a no no in the family, especially without consent. I asked her to return the favor, the proper thing to do, and she told me 'to fuck off'. Mom punished her and we haven't fucked since then, but I won't say she hasn't tried. She's grown larger and more dominant since then and I've tried to avoid situations like this, but this body was new to this version of me.

It's been almost a year, and now here we are. My will to resist was slipping and I'd put myself in a compromising situation, knowing that Kate will take advantage of this and likely fill me again and feminize me further. Not to forget that only a week ago I was riding Trish and came upon her cock, pushing her over the edge inside me. I forgave her, but we haven't fucked in a week... so I was feeling especially concerned as I considered letting myself give in to this pleasure.

Just then, a voice echoed in the hallway, "What's going on here?"