B.B.B.W.E. ***

Twilight was concerned for her brother. When he told his family that he had fallen in love with a changeling, they thought he'd gone crazy. Even now, Twilight wasn't happy about Shining Armor's choice in a mate.

“I mean sure,” Twilight thought, “Cadance may have been evil incarnate, but at best she wasn't created for the express purpose of killing Shining Armor the first time they met! Shining needs to be with a pony. Somepony that can give him children. Somepony who is smart, and funny, and is great with magic, and willing to read stories to him in bed..."

The more she focused on the mental image of the perfect mare for her brother, the more unsettled Twilight became.

“Shining needs a mare like me,” She thought. The purple unicorn buried within her vast intellect another lustful impulse directed towards her brother.

It was midday as she walked the long halls of Canterlot Castle. Twilight made her way towards her brother's chambers. Between his marriage and his work, Shining had hardly spent any time with his family. The last big thing they had done together was to kill Cadance, and you certainly couldn't classify that as a vacation.

As she approached the closed door, Twilight could hear the squeaking of bed springs and the moans of carnal pleasure. Twilight blushed.

“I should have called before I came over,” she said. The purple unicorn turned to leave, when she stopped herself.

“You know,” she thought, “field studies on changeling mating rituals is sparse, at best. I owe it to the scientific community to witness these acts.” Twilight crept back to the door.

“For science,” she whispered, as she carefully pushed the door open slightly.

Twilight had to stifle a gasp. She wasn't prepared for what she saw. Shining was sitting on the bed, pumping his cock furiously into the ass of a purple unicorn mare. He was taking her diamond doggie style. She had a very familiar cutie mark; a six-pointed star. It was Twilight.

“Twily, your ass is so tight,” Shining said, sweating.

“Your cock is so hot, big brother!” his lover said, “Harder! I want it harder!” Twilight watched from the door as her brother increased his speed on her purple doppelganger.

“That's me,” Twilight thought as she blushed, “Did my future self travel back in time to have an affair with my brother?” Twilight stopped for a moment to consider the fact that she lived in a world where that was a legitimate possibility.

“I'm not hurting you am I?” Shining asked.

“Not anymore,” the purple unicorn replied, “In fact, it's starting to feel really good.” The other Twilight opened her eyes, and for a moment, they were green, with reptilian pupils.

“(gasp),” Twilight said, “Of course! The changeling has shapeshifting powers!”

Twilight's voyeurism had quickly escalated from pure, scientific research, to clopping material. Watching her brother screw her exact double in the ass had made Twilight incredibly horny.

She looked down the spiraling staircase hallway. She couldn't hear anypony approaching. Canterlot Castle was huge; the odds were against anypony walking this way anytime soon.

“Perfect,” Twilight whispered as she lay on her back.

Once she was comfortable, Twilight turned her head to look at her brother and his wife make love. Using her advanced unicorn magic, Twilight conjured the spell that all lonely mares cast in times of need: a phallic-shaped force field.

Twilight was already pretty wet from watching the display. She levitated her purple, glowing, magical dildo and rubbed it against her pussy. She stifled a small squeak each time it rubbed against her sensitive clit. Not taking her eyes off her brother, Twilight floated the wet dildo over to her face and shoved it in her mouth. She licked off her femme lube as she tried to match her thrusts with those of her brother.

Once her torpedo-shaped force field was coated in her saliva, she moved it down to her puckered, dark-purple asshole. Not having anypony to prepare her butt, Twilight knew that this would be hard going. It didn't matter how wet the shaft was, it was entering a tight, dry sphincter.

Twilight slowly pressed the tip of the dildo against her tail pipe. She strained as her asshole began to open and the tip slowly worked its way inside.

Twilight took a moment to take some deep breaths. Her face was flushed. Taking her eyes off her brother for a moment, the mare watched as the dildo disappeared further and further into her poop chute. Not content with anal stimulation alone, Twilight moved her left fore-hoof in a circular motion around her clit.

When she had bottomed out in her ass, Twilight started moving the dildo in and out. Not being a real cock, there was no precum to keep things slick. Once the saliva was used up, the going got really rough. Twilight pulled out the dildo and looked at it.

“I've heard that some mares do ass to mouth,” Twilight thought, as she inspected the dildo for cleanliness, “I can't help but question the sanitary implications.” She stared at her purple pleasure proxy penis. It looked clean enough.

“If it was for Shining Armor, would I do it?” the mare asked herself.

“Of course,” she said, answering her own question.

Bringing the dildo close, she sniffed it. Her nose wrinkled. The object reeked of her rectum.

“I'm sorry big brother,” she said quietly, as she opted to slick the dildo back up by rubbing it against her pussy lips, “Not even for you.”

Once she had given it a second coat using her love juice, Twilight found that inserting her glistening force field was much easier the second time. Her ass was already stretched from before, allowing her to slam it in deep on the first thrust. Twilight started to pummel her own ass, her butt keeping a tight grip on the dildo. While this went on, her hoof kept teasing her g-spot.

Growing up, Twilight pretended that the feelings she had for her brother weren't there. But now, the purple mare was so happy. Before today, she had never known that her brother felt the same way about her.

“It all makes sense now,” Twilight said, smiling, “Why else would he marry a changeling?”

She could tell the couple was nearing their orgasms. In order to prolong their sex, Shining Armor slowed his pace. He kept slapping his hips against the changeling's ass in a certain rhythm; one that seemed familiar to Twilight. As she listened to the beat, Twilight recognized it as the same tempo as the song Twilight sang to him when they was little.

While her brother provided the beat, Twilight provided some new words to their song, in the key of Db Major. Even though she was singing too quietly for Shining Armor to here, Twilight dedicated this song to her brother, and she meant every word.

[Twilight Sparkle]

When I was just a filly, I tried to suck his willie.

He told me it was really wrong to eat his meat.

I tried to shun incest, but as I grew older it seemed best.

Shining's member will make my life complete.

He's the one colt I'll spread my bum for,

I wish that he would cum on me.

My big brother, best wincest ever.

Like two peas in a pod, we did everything together.

At least we did inside my mind, (Best wincest ever.)

I'd let him take me from behind. (We did everything together.)

He'd share his cum, my ass he'd ream,

I woke to find it all had been a

wet dream...

[Shining Armor]

My kid sister, best wincest ever!

Like two peas in a pod, we did everything together!

[Twilight Sparkle]

And though he's married to a bug,

I want him in my rug.

My big brother best win-

-cest ever...

-cest ever...

“Shining Armor, I'm cumming!” Twilight screamed, as she picked up the pace; jackhammering her own ass.

“Me too, sis!” Shining Armor said, thinking it had been his wife who had announced her orgasm. Both siblings came. Twilight squirted her femme jizz on the stone castle floor. Her brother unloaded the contents of his balls into his wife's tight ass.

The only one who remained unsatisfied was Chrysalis.

“But I haven’t cum yet.” she said.

“I'll fix that baby,” Shining said panting as he pulled his cock from her ass, “Wait a minute. Then who screamed my name?” Twilight was flushed with embarrassment. She teleported away just as the couple turned and saw the crack in the door.

“I think somepony was watching us,” Chrysalis whispered. When Shining opened the door, there was nothing there but a small, slick puddle. As he looked down the spiraling staircase, he saw no signs of the peeping pony. Shining Armor then returned to his wife.

“If somepony was there, they're gone now,” the stallion said, as he repositioned his wife; preparing to mount her pussy.

Meanwhile, Twilight sadly walked the Canterlot Gardens alone. Everypony thought his brother was still married to Princess Cadance. They couldn't be together. She sang a melancholy reprise of her song.

[Twilight Sparkle]

He was my big brother, best win-

-cest ever...

And now, we'll never screw anywhere

Together...

Shining Armor succeeded in bringing his wife to orgasm.

"Come for my, Twily!" he shouted, straining himself as his wife's pussy milked his cock, "shoot your green jizz all over your big brother's dick!"

What nopony noticed was the low hanging cloud outside the couple's window. Shining Armor had neglected to close the blinds this time. Some pony was spying on them from outside their Canterlot tower bedroom.

“Beep beep” came a voice from within, “I'm a cloud.”

The pony's entire body was covered by the white, puffy fluff; all except for her pink horn, which she was using to levitate a camera. She had taken photos during Shining Armor and Chrysalis's entire lovemaking session. Pictures that showed the caption of the Royal Guards in a scandalous incestuous relationship with his sister.

"Revenge is a dish best served on glossy 8 by 10's." Cadance muttered to herself.