Sweetie was practically shaking with hidden excitement as Rarity took her up to their bed. It had been some months since they had come to an understanding on their new relationship, and they had been as close as it was actually legal to be ever since. After a long period of subtle advances and displays of cuteness, she was now hopeful that her goal was about to be achieved. Rarity had seemed uncomfortable and fidgety all day. She was obviously in heat, and Sweetie finally felt secure enough in her affections to make her ultimate move.

She let Rarity start to tuck her in, then put her plan into action, “Why don’t you go to bed at the same time as me tonight? You’re always complaining that you’re tired when you have work keeping you up, but you don’t try to catch up when you don’t.”

“Well, I suppose so. I am feeling a bit off today, with any luck it will have gone away by the time I wake up tomorrow.”

“I’m sure it will,” Sweetie smiled innocently up at her sister. She shuffled over slightly as the mattress tilted under Rarity’s greater weight. She snuggled up to the mare, buried her face into the graceful neck, and then she waited. Eventually she heard her sister’s breaths slow down, and soon afterwards she started to feel the slight twitching which meant that Rarity was wrapped up in an uncomfortable dream. Between the state she had been in throughout the day and the burning heat that Sweetie Belle could feel against her shin, there was really only one thing that the dream could be about. Sweetie wriggled slowly up until their muzzles touched. After pausing for a moment to feel Rarity’s heavy breaths in her own nostrils, she licked her lips and pressed them gently against her sister’s closed mouth.

She pressed on the soft lips repeatedly, never breaking contact in between, and the little pushes within the drawn out kiss slowly opened the sleeping mouth for further exploration. The little filly had soon opened a gap wide enough to accommodate one of her lips. Taking one of Rarity’s lips inside her own left her heart hammering and her lungs heaving; better yet, her sleeping sister was reciprocating passionately. Sweet as the situation was, it was over quickly. With both ponies so excited it only took a moment to go from there to lustful, hungry snogging. The thick, flat tongue lapping at the insides of her mouth sent Sweetie up to a new level of joy. Guided more by enthusiasm than by ability, she started to rub at Rarity’s slit with the side of her hind hoof.

Then Rarity pulled away. Her head hovered just over the pillow, inches from Sweetie’s own, her eyes wide. Sweetie quickly pulled herself over her and rejoined their lips. She was gambling everything on their newfound bond, the raging of her sister’s loins and the feeling of her own young body pressed up against her. The Lady was smiling on her. Rarity plunged strait back into the kiss, and then rolled the filly over.

Their lips broke apart again and Sweetie felt Rarity trailing a line of kisses down her body, not tenderly like in those books she had for when she was alone, but fiercely and urgently. Sweetie felt the muzzle being pushed into her thick fur again and again, but in such a rush. She felt one which had actually got down to the soft belly between her hips, a drawn out kiss finally savoured, a hard suck which actually put her skin in Rarity’s mouth, another withdrawal, and then a pause. She lay unmoving as she enjoyed the feeling of her sister’s hot breath surging against the insides of her thighs. A hoof came up and pulled one of her lips aside, laying her tender insides bare. She felt Rarity’s head glide in closer between her thighs. She couldn’t stop picturing that wide, rough tongue pushing deep inside her, flooding her with satisfaction. She felt another kiss, so light this time that it hardly touched, and then the head withdrew half a foot.

Her hind legs started to shake, her slit was dribbling softly and she felt ready to scream. Then Rarity slowly traced the inside edge of her lip with the tip of her horn. Without meaning to, Sweetie whinnied pleadingly. The teasing ivory point moved slowly over to sit loosely against her opening, sending her vision blurry with pleasure and longing. It pushed in, taking several seconds for every inch, and didn’t stop until it was buried right up to its thick base, so that she could feel her sister’s forehead against her tender flesh. Rarity started to draw back out, slightly more quickly, and time lost all coherence.

Sweetie had everything she wanted, she had it completely and utterly, and it was bucking her brains out.

Author's Note

First attempt at big descriptive clop, so tell me what you think below (as ever). Sorry for how long that took to finish; I never really managed to portray Rarity’s conversion well enough for my mind, but I decided that I never would be able to, so I just posted the best that I could do.