Estrus among us

The next morning, Cheerilee opened her eyes, only to find herself lying facedown on a couch. She took a few moments to get her bearings and try to remember the night before. There had been a wild party in the middle of town, and some sort of spell had been cast that had made her teats grow to enormous size. She sat up and looked around, letting the blanket fall off her back. Looking down at herself, she saw she was back to normal, but she was still dressed in the slutty outfit she'd donned to go out. Her head whipped around at the sound of heavy footsteps coming down the stairs to her right. As she stared, the Human came into view. He smiled when he made eye contact with her, and said, "Good morning! Did you sleep well?" Then all her memories came crashing back. The party. Her lewd invitation to the Human. Him bringing her back to his home. All that happened after. She finally blushed and looked away from him. How could she be so brazen? What would the other ponies think?! She had to get home! She got fully to her hooves and began to rush out the door, then stopped. There was no way she could be seen in the daylight dressed like this! So she sat back on the couch and slowly started to undress.

Alex seated himself across from her on his recliner and watched her with concern. "Are you okay?" he finally asked her.

She stopped unbuttoning her top and spared him a brief glance, then continued undressing. "Yes...yes, I'm fine. I just...can't be seen in this costume." She got her top undone, then quietly slid one shoulder out, then the other. She took a moment to fold it neatly and place it on the couch next to her. Next, she stood, turned her back on him, and slid her miniskirt down. It made a soft "shusssshing" sound as it slid past her ass and down her stockings. Alex's eyes were glued to her ass as it was revealed while she dropped the skirt to the floor, stepped out of it, then bent at the waist to pick it up and fold it as she'd done the top. Then she sat back down, crossed her legs, and began to unroll one of her stockings down her shapely thigh. A feminine instinct made her stop.

A horny male was staring at her.

She looked up, and there was the Human with his eyes locked on her, with a hungry expression on his face she had no trouble reading. Her gaze traveled slightly downward and saw his cock was fully erect, straining through his pajamas. She bit her bottom lip, thinking. She'd already crossed one of her taboos when she'd demanded he fuck her in the ass last night, and she'd greatly enjoyed it, she admitted to herself. She might as well go full slut and give him a blowjob. "Pull down your pants," she whispered. Alex quickly complied, until they were around his ankles. His cock stood straight and tall and throbbed as she stared at it. It was so big! Would she even be able to fit it in her mouth? One way to find out.

She pulled her stocking back up with a snap, then slowly approached him. When she got between his legs, she went on her knees and spread his apart and gazed smokily up at him. "I'm going to suck your cock. Don't tell anypony...this will be our little secret..." With a sultry smile, she lowered her head and buried her snout in his ballsack, taking a deep sniff. His male musk flooded her senses and made her mouth water. She closed her eyes and stuck out her tongue, taking a long, slow lick from his balls all the way up his shaft to the head of his dick, where a pearl of precum was waiting for her. She lapped it up and smacked her lips, enjoying the flavor. Holding his cock steady with her soft hooves, she swirled her tongue around the head, which made him gasp and slightly buck his hips. Interesting. So he particularly liked it when she did that? She experimented with different parts of his dickhead, trying to find the most sensitive areas to lick and suck, finally settling on the glans just below the opening. When she ran her tongue there, he would cry out and spurt more precum for her to enjoy, which she eagerly sucked up and swallowed it all. Then she wrapped her lips tightly around his shaft and bobbed her head up and down, taking more and more of his meat into her mouth, leaving a trail of glistening saliva down the shaft as she sucked and slurped. Though she was too inexperienced to actually deepthroat him, she made up for it by deeply sucking and licking as much of him as she could. From the sounds he was making, she guessed he wasn't disappointed, which made her smile around her mouthful.

After a few minutes, he buried his hands in her mane and moaned her name, adding thrustings of his own to her bobbings. Warmth spread through her from her ears, down her neck, around her throat, and finally settling on her lady parts. She added her own moans to his as she quickened her pace, slurping louder and faster, causing his cock to press against the back of her throat, almost making her gag. But she took it all, determined to swallow everything he was about to give her.

She didn't have long to wait.

With a final cry and thrust, Alex arched his back and pushed his dick into her mouth as deep as he could, pumping his hot, sticky loads of cum over and over into the mare's throat. She closed her eyes and began gulping, trying to keep pace with the sexy work she was forced to endure, while at the same time her cunt began convulsing and throbbing with the intensity of the sudden orgasm that came upon her. In the end, she took one last swallow and pulled off him, as they were both left breathless from their combined ordeal. She lay her head on his lap as she panted, while his now limp dick draped itself over her face, with the last flow of cum still leaking out of it and over her. After she caught her breath, she raised her head and took it into her mouth once more, sucking every last tasty bit, then licked his balls clean. Then she sat back, took a hoof and wiped all the cum off her face, then popped it into her mouth as he watched her. She smiled, then without a word went back to the couch, quickly removed her stockings, then took them and the rest of her costume and placed them on her back. When she stood, an errant thought occurred to her, and she took a hoof and felt around her nether regions. Then she glanced around for a moment, then looked up at the Human. "You...haven't seen a pair of panties anywhere, have you?" Alex watched her as he reached up into the breast pocket of his pajamas, and took out a wad of cloth. He held it between his fingers and let it fall open, revealing it to be the item she'd been looking for. She looked from them to his face and back again, then smiled. "Keep them." As she headed for the door, Alex pulled up his pajamas and followed her, then opened it for her. Just before she left, she turned around, then moved in close and gave his crotch one last kiss. "See you later, Big Dick..." She winked up at him, turned, and left.

A week later

As the Sun was just creeping through the window, illuminating the prone dragon, Spike opened his eyes and sat up. He yawned and stretched, then got slowly out of bed. He went to the window and looked out at the cityscape of Canterlot, already bustling with ponies, minotaur, griffons, and other denizens of Equestria. He turned and went to the bedside table, where he kept the letter he'd received from Twilight a few days ago. It was wrinkled and tear-stained from being read over and over again:

Dearest Spike,

I hope this letter finds you well. I want you to know I know why you left, and I'm sorry if my actions had anything to do with your decision. Please understand, that no matter what happens between us, you will always be my Number One assistant, and my Best Little Brother.

To this last, I have considered the fact that you might not be quite so little, after all. While we still know very little about dragon aging, you are quite mature according to pony standards, as you were hatched when I was entering Celestia's School for Gifted Unicorns.

The bottom line is you are an adult, Spike, and you have been, even before Alex changed you. So you are free to do anything consenting adults are free to do with each other. But that's your decision. Know that whatever you decide, I will always love you, and I promise nothing will change between us. Nothing.

Please come home, Spike. I miss you.

With all my love, Twilight

Spike put the letter down once more and turned to the window, where he had a distant view of Ponyville. Through the tall buildings and assorted shops, there was still a faint glimpse of his home, and it filled him with loneliness. There, going about their daily lives, were all of his friends and the rest of the family he had ever known in the personification of the purple, book-smart, obsessive-compulsive, nerdy unicorn turned alicorn, who, for all intents and purposes, had told him in a letter that she was quite agreeable to a sexual relationship with him. He searched his innermost thoughts and tried to be as honest with himself as he could. Is that what he wanted? Could he go from being her best friend, little brother, and Number One Assistant...to her lover? Could he compete with the Human, who had only arrived in town for a few weeks, but had already made such a profound impression on her and other mares? He shook his head and put the decision off for another day.

Still not accustomed to his new size, he then lumbered out his door and down the hall to the upstairs bathroom and turned on the shower. He stayed under for several minutes, just letting the scalding hot water wash over him, in a vain attempt to rid himself of the overpowering pheromones his body now produced.

But he'd forgotten to lock the door.

As he got out of the shower and reached for a towel, the door opened, and there stood his surrogate Mom, Twilight Velvet. Her eyes were immediately drawn to his massive penis, and she blushed. "Oh! Sorry, Spike! I didn't know you were in here!" Spike hastily wrapped the towel around himself and frowned.

"Ever hear of knocking?" His voice was still the deep, masculine bass from a few days ago when he'd first transformed, but he still wasn't used to it. Nor was he used to the reactions he'd gotten from just about every mare he'd encountered from Ponyville to Canterlot. Ones that would have only seen him as an oddity not long before were sidling up close to him to get a whiff of his new scent or stare at him with undisguised desire in their eyes.

He wasn't quite sure how he felt about it.

Twilight Velvet blushed again and backed out, stammering, "Please excuse me, Spike! I...I'll just be going now." With one last brief glance at his crotch, which he didn't miss, she turned and bolted out the door. Spike sighed and made his way back to his room. He went to the bed and sat down, rested his head on his claws, and stared out the window. Just a few days ago, he was his normal self. He was with Twilight, he had his friends, he had everything he could have hoped for. And now? Now...he was a magnet to every mare within nose-reach...even his Mom. He'd left Ponyville because he'd seen the pressure he'd been putting on Twilight, and he didn't want to do anything to ruin their relationship. If he'd stayed, they probably would have had sex by now. And a small part of his mind wondered if that would really be so bad a thing? What if it makes her happy? He'd seen how she'd changed after she'd started a relationship with the Human...how she'd been less compulsive and more giddy. She seemed happier...more...free. Couldn't he do the same for her?

As these thoughts were swirling in his head, there came a knock on his door. "Spike? Can I come in?" Spike sat up and turned around. He recognized the voice, but he hadn't heard it in months.

"Sure, Cadence, come on in." The door opened, and in trotted the Princess of Love. As soon as she cleared the doorway, she stopped, closed her eyes, and took a long sniff. Then she opened them and smiled at him.

"I see what Twilight Velvet and the other mares were talking about! That's quite the male scent you have now!" He watched her as she closed the door, then came and sat next to him. "So! Your parents wrote me and told me what you were going through. You want to talk about it?" She noted his expression as he looked at her, then stared back out the window. "What's wrong?"

At first, she thought he wasn't going to answer, then after about a minute he said, "Every mare that gets a whiff of me wants me."

She smirked. "Is that a bad thing? Most males would kill for the chance to be in your hooves. Er...claws."

Spike threw up his claws. "That's just it! I don't know if they want me for me, or for what I've become!"

Cadence shook her head. "You're overthinking it, Spike. The real question is: do you desire any of them?" He was taken aback by her question and had to give it some thought.

Finally, he said, "I suppose I do...but I don't want to just go around banging every mare I see."

She nodded. "Is there...a particular mare you have in mind?" He immediately thought of Rarity...the one he'd desired from the moment he'd met her. But she'd always treated him like a close friend and had never given any indication he'd ever be anything else to her. Besides, he suspected she was also involved with the Human now, and the last thing he wanted was to be a third wheel.

Then, reluctantly, his thoughts strayed back to Twilight. Her smile. Her laugh. Her quirky ways. He smiled to himself, remembering all the times he'd caught her fallen asleep at her desk over some book, mouth open, slightly drooling, and snoring. It was always the cutest thing he'd ever seen and melted his heart. With that last thought, he came to a decision.

He turned back to Cadence and said, "In other circumstances, there might have been two. But one is already taken...and the other is somepony I don't ever want to change."

Cadence smiled again and placed a hoof on his leg. "So...the field is wide open, then?" She laughed at his expression and added, "Oh, I remember what you said about "banging every mare you see." But understand, to have the kind of influence you now have over females, while having the willpower not to take advantage of anypony, is quite noble." She took her hoof from his leg and said, "I have another question: do you want to stay the way you are?"

Her question startled him. "Wait...you can change me back?"

She nodded. "I think so. Before I came here, I met with Auntie Celestia and we had a long talk about Humans and their past influences in Equestria. They've been showing up for centuries, and we've acquired a vast amount of knowledge concerning them. What was done to you is similar to an effect that was done before, a long time ago, and the spell she taught me should work. But there are no guarantees." Before he could answer, and seeing the conflict on his face, she smiled once more and whispered, "Let me ask you this, Spike: how do you like sex?"

He blushed and fidgeted under her gaze, but finally said, "I've only had the one experience, but I really liked it. A lot!"

She then used her magic to lock the door. "Then before I change you back, if that works, I should probably give you a taste of what you'll be giving up..."

Spike frowned.

Later that night, Twilight was awakened by a knock on the front door of the Library. She sat up, rubbed the sleep out of her eyes, then dragged herself out of bed and down the stairs to open it. It had better not be Rainbow, coming over for a late-night snack again, she thought to herself. When she opened the door, she gasped in joy.

There stood Spike, gazing serenely at her. Gone was his imposing height. Gone were the intense pheromones. He wasn't quite as short as he was before, but none of that mattered! She quickly enveloped him in a crushing hug and covered his face in kisses while crying out, "Spike!" >smack!< "You're back!" >smack!< "I missed you so!" >smack! smack!<

Spike smiled and patted her back. "I...missed you too...Twilight. But...can I ask...a favor?" he wheezed.

She tightened her grip. "Anything, Spike! For you, anything!"

"Could...could you let me...breathe?"

"Oh!" She opened her hooves and let him back down, which he did while taking in a huge breath. "Sorry, Spike! I'm just so glad to see you!" She used her magic to shut the door, then gestured for him to have a seat, which he did gratefully.

"Thanks, Twilight...it's really good to be home."

She sat down next to him and nuzzled him, then said, "You were only gone for a week, but it felt like an eternity." Then she looked down and away from him, her face slightly red. "I wrote you. Did you get my letter?" He took her gently by the chin and turned her face back to his.

"Yes, dear Twilight...I got your letter. I read it every day. It's why I came back." He let go of her face and stepped in close, folding his arms around her. "I love you, but I don't want to be your lover." He released her and stood back, looking her in the face. Tears formed in both of their eyes as he continued. "I want you to know I don't blame you for anything that might have happened between us while I was...you know." She nodded. He went on. "I saw how every mare I ran into reacted to me...I was pretty irresistible." He paused and took a deep breath. "But...it wasn't me. They...you...wanted what I had become." He looked down at himself, then flexed his claws. "Maybe one day, when I reach my larger size on my own, I'll be like that." He looked up at her again. "Until then, can we just be like we were before?"

She burst into further tears and hugged him once more. "Of course, Spike! Whatever you want!" She then released him, dried her eyes, and sat back down. The scientist within her finally awoke and she added, "So tell me, how did you revert? I can see you're not quite the same as you were before Alex changed you, but you're nowhere near the way you were before. What happened?"

Spike sighed. "It was Cadence."

Twilight's eyebrows raised. "Cadence?"

He nodded. "She came to visit me earlier today and told me she'd been talking to Princess Celestia about Humans. She said what happened to me had been done at least once before, a long time ago, and she knew a spell that could probably change me back. So she gave me the choice."

Twilight smiled. "And you chose to return to your old self. I'm glad Spike. I really am!"

He smiled back at her, but it was slightly strained. "So am I, Twilight." He left out the part of Cadence trying to seduce him... and his flat refusal. She'd taken it well, but if many moons passed before he saw her again, he would be fine with it, even though he was ultimately grateful for her help.

Spike yawned. "I'm pretty beat, Twilight. What say we get some sleep?"

She smiled and lead the way upstairs. When they reached the bedroom, they both stopped and looked down at Spike's old basket. The same thought ran through both of their minds: he was too big for it now. She turned to him, and in a shy voice, she said, "Spike, you used to cuddle with me when we both were little, especially when there was a thunderstorm outside. Would...would you like to again? Just until we can get you a bigger bed?"

He smiled back at her. "Sure, Twilight."

So that night they snuggled together, brother and sister, and they both had sweet dreams.