Sara Reynolds tried to be a good mother. Ever since her lying, cheating scum of a husband had left her and their son Joey behind, she'd done everything she could to provide for her little boy. He was six years old now, and Sara loved him more than anything else.

Sometimes, she thought she loved him a little too much.

A sick desire had been plaguing Sarah for the past year and a half. The desire wasn't a particularly new one, but she was horrified when it emerged again, stronger than ever. She tried to deny it, but the desire soon filled her every waking moment, and then her dreams. It burned like fire in her gut, and it increased each day.

Each day, as well, she had to drive past a sex shop called Susie's, open for twenty-four hours. Each time, she was tempted to go inside and have a look around. Each time, she didn't. But one day, while driving home from work, her hands twitched and she finally turned into the parking lot of the shop. For a while she sat in her car, heart pounding, before she went inside.

She found what she needed within fifteen minutes, and quickly, she left again. She was late to pick up Joey, but he'd forgive her. Joey, with his sweet, cute little smile and his gapped teeth. His chestnut brown hair and vibrant green eyes, just like hers...

Sarah shifted, pressing down into the driver's seat. She glanced at the rearview mirror, seeing the little nondescript black bag in the back. Inside that bag was a box. Inside that box was a strap-on, a thick, black phallus that was eight inches in length and two inches in girth.

For you see, there was nothing Sarah Reynolds wanted more in the world than to fuck her six year old son in the ass, and tonight, she was going to do it.

***

She pulled up in front of Joey's school, and he immediately hopped into her car and smiled that crooked, adorable smile of his.

"Sorry I'm late, honey," she said, reaching over and stroking his thigh. "There were a lot of cars and mommy got stuck."

"That's okay," Joey said, as bright and happy as ever. "I colored."

Satisfied, Sarah drove off, occasionally sliding her hand up her son's thigh. Her pussy burned with aching lust.

Once they were home, she ushered Joey inside, then grabbed the black bag and followed him. How was she going to do this? Was she really? Could she?

"Joey," she said. "You love mommy, don't you?"

"Of course!" Joey looked at her with wide eyes and a smile. "Lots and lots."

"You'd do anything for mommy, Joey?"

"Yup!"

"Anything at all?"

Joey nodded. "Mmhmm."

"Is that a promise?" she asked, sticking out her pinky finger. With all the naive innocence of a child, Joey wrapped his pinky around hers and shook it.

"Pinky promise," he said.

Sarah's panties were soaking. She couldn't wait anymore. "Go upstairs to your room, baby," she said. "And get undressed."

"Um... naked?"

"Yes."

Joey hesitated, looking at her curiously. Sarah just smiled and said "please," and Joey shrugged and walked upstairs, into his room. Hurriedly, Sarah opened the bag and removed the strap-on from the box. She slipped out of her pants and underwear, stepping into the harness. Attached as well was a smaller dildo that would penetrate her as she fucked, and she sighed as it entered her when she pulled the harness around her hips. A little knob rubbed against her clit, and she tightened the straps around her hips.

Good to go.

Last but not least, Sarah grabbed a bottle of lube, then walked up the steps to her son's room. Her pussy clenched tight around the little dildo inside her, and each brush against her clit made her shiver. She could just imagine plunging into Joey, and her desire burned hotter.

She stepped into Joey's bedroom, and like a good little boy, he was sitting on his bed naked. He took one look at the thick, black plastic cock extending from her groin, and he scrambled back a bit in shock. "Wh-what's that?"

"You said you'd do anything for mommy, right?" Sarah asked, voice husky with need. She walked over to the bed and grabbed Joey's ankles, pulling him towards her. His whole body was hairless and smooth, pale and perfect. Her hands slipped up his thighs, to his hips.

"M-mommy?"

"Get on your hands and knees, baby."

"But why!"

"Because mommy said so. Because it'll make me happy. Okay?"

Joey, confused and a little frightened now, slowly rolled to his hands and knees. She gasped when she looked at his round, firm little ass, then reached out and gripped the smooth cheeks firmly in her hands. Joey yelped and tried to pull away, but she gripped one of his hips and pulled him towards her.

Then, Sarah raised her hand, and brought it down hard on her son's left ass cheek.

He cried out in pain, and she did it again and again, alternating the cheeks. Joey cried and tried to yank out of her grip, but she always pulled him back and slapped him harder for his resistance. He screamed, asking why, but Sarah didn't answer. She just slapped and watched bright, red handprints appear on his perfect white ass.

Finally, she stopped, hearing Joey's sobs. Picking up the bottle of lube from the bed, Sarah popped it open and poured it on two fingers.

"W-why Mommy, w-was I b-being b-bad?" Joey asked, gulping for air between sobs.

"Ssh, you're being very good now sweetie," she said, spreading his ass cheeks apart. Then she pushed her index finger inside of him, listening to him cry out as she sank her finger down to the knuckle. She began to thrust her finger in and out, holding him down by his shoulder to stop him from bucking and wiggling. After a moment, she pushed her second finger inside, stretching out his tight, virgin ass. His six year old, forbidden ass.

Since Sarah's fingers weren't particularly large, she lubed up a third finger and began to push that into him, as well. Joey gasped and moaned in pain and discomfort, but she paid him no mind. She sank three long fingers deep into his tight ass, then began to fuck him with them, thrusting them in and out. Gradually, she began to fuck him harder, thrusting her fingers faster, and rubbing them against his immature little prostate.

Finally, she couldn't stand it anymore. Groaning with need, Sarah pulled her fingers from Joey's ass and pushed him onto his back. He looked up at her with pleading, tear-filled eyes. Breathing hard, Sarah grasped his ankles and pushed his skinny little legs up towards his ears, lifting his ass up in the air.

"Mommy needs this, baby," she whispered, pouring lube on the thick, black phallus. She stroked her hand up and down, and Joey watched in helpless horror.

"Pl-please no," he whimpered, as Sarah rubbed the thick, mushroom-shaped head of the dildo against her son's tiny, exposed anus.

Sarah pushed forward, mercilessly, until the tip was inside. She continued to push, and between his legs Joey watched the thick, black cock penetrate him. He started wailing all over again, and Sarah shoved a hand over his mouth to muffle him. She looked down, marveling at the way the thick cock stretched her son's rectum to the limit. She had already forced four inches up his asshole, but she wasn't satisfied until she had pushed all eight inches up his sweet little fuck hole.

"Oh god," she groaned, grinding her hips into Joey's ass, which in turn made her clit grind into the bump. "Joey!"

Groaning at the unbelievable pleasure of it all, Sarah slowly pulled her hips back, watching her son's asshole stretch out around the plastic cock, his rectum gripping it for dear life. She pulled back until only the large head was inside, then gripped Joey's hips and plunged back down, burying all eight inches inside in one brutal thrust. He screamed for that, and she started pumping into him in short, hard thrusts, slapping her hips into his ass.

"Joey, baby, such a good boy..."

Every thrust pushed the smaller cock deeper inside her and pushed against her clit. Before she knew it, she was coming, her pussy clenching up tight and her entire body tensing as white hot pleasure spilled through her. "Joey!" she cried, pumping faster, her moans mixing with the sounds of his sobs. She came again and again and again, until she was finally so exhausted that she had to stop and catch her breath.

"Your ass is mommy's now, baby." Sarah slipped her hands along Joey's ass, then slowly pulled out of him. He moaned in discomfort. "Say it."

"M...my ass is yours, mommy."

"Smart boy." She leaned down, kissing his cheek. "This is just between me and you."

Mutely, Joey nodded, and from there he was the slave to Sarah's twisted fetish.

---

I have a second part of this story in mind, so if you enjoyed this one, feel free to say so!