Twilight posed at the foot of the bed with her hand on her hip. My eyes were glued to her amazing figure. Her large eggplant colored breasts project off of her chest. Each one was topped with a prominent dark violet nipple and areola. Her flat tummy tapered to wide feminine hips. The V of her marehood was groomed with a patch of hair that matched the mixed colored mane on her head. Her bare pussy lips were visible and glistened. To either side of them was her pillar like legs, thick and feminine.

“Fufufu,” she leaned forward and got onto the bed on her hands and knees. “I’ll never get over how much more this body effects you each time it grows.” Her position stuck her large ass out in profile as her tits smooshed into a mind benignly erotic display between her arms.

Sensuously, Twilight crawled to my prone positon. “Let’s get rid of those pesky clothes.” Her horn glowed and my clothing disappeared. “There. It’s in the laundry room ready to be washed.” Twilight brought her head to mine, her body poised above me. I was breathing heavily. She stared down into my eyes as I looked nervously up at hers. Then she lowered herself onto me. Her lips descended onto mine. Her larger and more powerful tongue forced its way into my mouth, and it roughly overpowered my own tongue.

Twilight made a series of hmm and uuhm sounds as she to probed my mouth with her tongue indicating she was enjoying herself. Her heavy weight was resting on me.

It was almost a minute before she let me up for breath. I was gasping for air and seeing spots. Twilight exhaled too. She gave a toothy grin, satisfied. She repositioned herself on her haunches. Her muff was on my stomach and her powerful ass was getting poked by my rigid member. The room was filled with her powerful, pungent musk and as I struggled to regain my breath, Twilight's scent filled my nostrils.

Then

"What happened?" I asked the altered mare in wonder. "I don't know." Twilight had responded. She had clearly grown over night. She was clearly taller, her head rising above my shoulders. "Look at this," she said. Twilight's horn glowed faintly and a book from across the room levitated over to us. "Your magic! You can do magic again." I was happy for her. She'd been having a rough time without being able to use her magical abilities. She smiled and nodded. "But how? Does this have to do with your growth?"

She paused, then answered my question. "If I had to guess. This happened after you and I..." She blushed. "Had sex," I supplied. She nodded. If only I'd known how quickly she'd get over that shyness about that. She moved forward. "There is something about you, your scent and your, stuff. It's heady. Intoxicating." She placed a hand on my chest as she looked up at me. "I think you humans have great innate magical energy inside of you that you've built up a resistance too. There isn't ambient magic in this world for me to use. When I consume that energy, my body stores it." Hence her growth.

"Makes sense." I nodded. Before I could ask anything else she shook her head. "But we really need to test it."

Now

“That was a good start.” Twilight purred. Her hands rose to run through her mane. Her ears resting on top of her head twitched. A reminder that this girl was was not quite human. Her tail was another and if she wasn’t so much bigger than me it would be brushing me right now.

I was trapped between her powerful legs. She was not resting all of her weight on me thankfully. At her current size, well I haven’t said anything, but her weight has to have doubled since she first changed.

“Now, my dear roommate.” Twilight lifted her heavy ass up a little off of me. “I’ve been good mare and I need my filling.” She reached down and took hold of my stiff member. She guided it to her dripping pussy and breathed sharply as I penetrated her. “Tha-ts it.” Twilight settled down onto me. All restraint was forgotten and I winced at her heaviness. I leaned my head back. The mixed sensations of sex and pain were flooding me. My hands reached up along her thick juicy thighs to those perfect hips. I couldn’t reach her tits when she sat straight like that anyway. My fingers sunk into her thick flesh as Twilight gyrated herself on my manhood. “Uh, ooo that’s it.”

Twilight leaned down so she could kiss me again. The combined sensation with our sex and her weight was driving all the air out of me. “I don’t know if I can survive too much more of this.” I thought as Twilight roughly probed my mouth. After a while she broke off and sat up again, her eyes wildly staring into mine as her hands traced my torso and shoulders.

I decided to push my luck and as she lifted herself up off of me a little I took the given room to ram up and forward into her. I’d apparently hit gold from her reaction.

“OOOOO,” Twilight squealed in surprised delight. I must have hit her G spot. She straightened and began ramming herself onto me faster. I winced as her ass slammed into my hips. Her hands had left her exploration of me and had begun squeezing and kneeding her jiggling breasts. I was going to feel this in the morning.

“Twi-Twilight!” I gasped and gripped her hips hard as I thrust into her. “I’m cumming!” Her eyes opened a little and looked down into mine. “Good. Good my precious little roommate. Cum in me. Give me your magical cum!” I obeyed her. I began to match her increased rhythm. Within moments I came inside of her. Twilight joined me with her own climax shortly after. Her hips slowly, jerkingly milked me in the afterglow. Soaked in sweat and bodily fluids, Twilight collapsed onto the bed beside me and spooned me into her big form.

Meanwhile, from the cracked doorway a pair of glowing green eyes took in all that had happened.

Author's Note

Thank you for your patience, hopefully this chapter delivers some smutty goodness.

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