This story was given to me by my friend Puffin777. His suggestion was a bit long so I'm just going to sum it up by saying it's about Toothless and Luna becoming giant and one day decide to have sex with their new sizes. Puffin, I hope you enjoy this.
Toothless had finally returned to The Hidden World to claim the throne as the King of Dragons, and has brought along his loving Light Fury wife, Luna, as the Queen. Of course, the return did mean that he had to leave behind his best friend in both worlds, Hiccup, but to both of them, it was for the better.
Once they move in, they get settled into their den and were ready and excited to start their new lives as king and queen.
Things started out pretty well, during the first two weeks, Toothless had sent his dragon friends to all corners of the archipelago and beyond to let any dragons that didn't live on Berk know it's time to come home. During that time, he saw a bunch of old friends coming in that he hadn't seen in years. Windshear, Smidvarg and the Night Terrors, Torch, Sleuther, Shattermaster, Garf, even Thornado. A few dragons like the Skrill, the Shadow Wings and the Screaming Death were a little suspicious about leaving, but when they found out who was king, they all had to come down and see. One dragon that simply could not leave, however, was the Defenders of the Wing Eruptodon, as he had to say in order to eat the lava from their volcano in order to protect the village which Toothless fully understood.
After those weeks, however, both Toothless and Luna noticed that their cave seemed to get a bit smaller and they couldn't figure out why. It took a visit from Cloudjumper, 3 weeks after moving, that they noticed that they were both eyelevel with the Stormcutter who was normally at least twice their size. They then figured it out, the cave wasn't shrinking, they were both growing. Growing at a rate of half a foot a day. Why this was happening, neither of them could figure out, so they decided to speak to the wisest dragon they know, Drago's Bewilderbeast who, after Toothless took over as Alpha, had turned away from his tyrannical behavior that he adapted from working with Drago and is now there to give advice to dragons using his vast knowledge.
Toothless and Luna talk to the huge dragon and it seemed that he knew what was going on. "I believe I've heard of something like this. Huge dragons like myself are the usual candidates for being Alpha, but if an average sized dragon, say a Night Fury, were to become an Alpha then the power that it gains will be too much for its small size so its body expands and grows."
"What about me?" Luna asks.
"The same thing. You became mates with an Alpha and you're average sized as well, so you gained the same amount of power that Toothless did and it's causing you to grow as well."
Toothless and Luna try to process what the Bewilderbeast is saying. Toothless then asks, "How large are we going to get?"
"Not too sure. Given your usual size I might say you'd be shy of as large as a Red Death, but that's just a guess. I would suggest you both find a larger den. There's an old Red Death den from when the old queen lived down here, that might be a good spot."
Toothless and Luna thank the Bewilderbeast for helping, and they head back to their current den. Sure enough, a month after moving, they are simply too large for that den, both of them are around 35 feet tall and 100 feet long. Also, Toothless had also outgrown his prosthetic tail fin, so he had to take it off and now relies on Luna to take him where he needs to go. With nowhere else to go, they try out the den that the Bewilderbeast suggested. It seemed quite large at the time, but given that they don't know how large they're going to get, it was good to be safe.
So, from there they lived out their lives as normal as possible. Of course this didn't mean the rest of the dragons didn't notice that their king and queen have grown significantly since they first arrived. Fortunately, Toothless's closest friends were there to keep those nosy dragons at bay as they understood that they were both going through a difficult time.
Through each day that passed, they just kept growing and growing while also hoping and hoping that their growing stops at some point and they could possibly even begin shrinking back down to normal size.
Sadly, things did not get better over time. Within the following month they had grown to the point where they could just fill out the den, each reaching about 90 feet tall and 350 feet long from nose to tail. And they were only getting bigger. Their growing rate had somehow increased to at least a foot a day, which troubled them even more. Toothless figured that one benefit of being so tall is that he can watch his dragons from a much better height, but that was about the only positive thing he could think of.
It finally got to a point where they had become too big for even the Red Death's den which, besides the Bewilderbeast's, was the largest den in The Hidden World. This left Toothless in Luna with only one option, one that they knew would affect every dragon down there.
Toothless had assembled a meeting near the King's Crystal. Once everyone was there he began to speak. "Thank you all for coming. Now, as you know, my wife Luna and I have somehow grown a bunch over the past few months. Now, because of this continuing growth, we have actually outgrown every den in The Hidden World. So, it is with great sorrow that I announce that Luna and I will be leaving The Hidden World and going back to the other world, the human world." Looks of shock and sadness filled the room. "I know, I just got back here and just claimed my throne. However, the throne is useless if I can't even fit into my own home. I am sorry to have to leave you all like this, but it does need to be done. Hopefully I'll find a way to shrink back down, but if I don't, then I trust you all can take care of yourselves. I'm sorry everyone, but there's nothing I can do."
With that, Toothless and Luna made their way past the crowd on their way out of The Hidden World. Once they got to the egg caverns, they had to be careful not to crush any eggs and seeing as how Luna's wings were too large to fly properly in such a tight space, they resorted to clinging to the cavern walls with their claws. They get to The Hidden World's entrance and, due to her now massive wingspan of 500 feet, Luna was able to get to the top of the falls with only a few flaps. They settle for a nearby island that seemed to be large enough to accommodate both of them.
Once arrived, they both stare back out into the direction of The Hidden World's entrance. Luna couldn't help but start crying at the situation, so Toothless wrapped a wing around her and held her tight. She says through sobs, "Oh Toothless. What are we going to do? Where do we go? Is this our lives now, as two lone giants?"
Toothless holds her even tighter. "Hey, Luna. It's ok, we'll figure something out, I'm sure of it. And we're not alone, we have each other, and that's all I need." This helped Luna a bit, but she was still pretty upset over the situation. Toothless tried to think of some way to make her feel better, but had a pretty hard time. Then, a thought comes to mind. "You know, I do know one thing that always helps you feel better."
Luna knows what he means and looks up to him. "Are you seriously talking about mating at a time like this?"
Toothless shrugs. "Who said anything about mating? It just seems like you're a little down and I thought you could use a pick-me-up. What we do for that is totally up to you." As he says this, he subtly allows his member and balls start to slip out of their slits. His member starts poking Luna in the stomach, and she notices quickly.
She still had tears but giggled a little. "Toothless, what's that I feel there?" Toothless gave the best 'I don't know what you're talking about' face he could give. Luna wiped away her tears and says, "Oh, you sexy stud. Come here." She tackles him into the ocean, causing a big splash.
"I knew you'd come around." He says with a smirk.
"Oh hush. Now, let's see what this new you is packing." She moves down, closes her eyes and starts licking the tip of Toothless's cock and his balls, effectively coaxing it out more. Once a bit more was out, she reaches a paw up and strokes him, making him moan with pleasure as his tapered cock slid out and grew to a full erection. Luna pauses licking his balls and open her eyes to see just what she was dealing with. "Ho. Ly. Shit." Was all she had to say upon seeing the massive member.
Before the growing began, Toothless was already pretty hung with his cock reaching about a foot and a half in length and 5 inches in wide at the base when fully erect, and that didn't include his mango sized knot right below the base plus a set of coconut sized balls. Now that he was grown, his cock reached a whopping 20 feet in length and a foot in girth at the base, and his knot wasn't even out yet, plus his balls were as big as he used to be.
Luna moves up a bit and licks the tip of the cock before putting it in her mouth while her front paws continued to stroke the giant length. She always loved the taste of his cock, and somehow being so much larger made it that much more enjoyable. Toothless placed his paws on her head and made her bob up and down the cock, sending waves of pleasure all throughout his body. A bit of pre-cum leaked from the dick, which Luna licked up immediately, not wanting him to waste a drop.
Toothless is enjoying himself entirely, but there was something he needed to see. "So, when do I get to see what you're packing?" Luna looks to his eyes and smiles. She gets off of the cock and turns around so that he massive vagina is now hovering over his head. When normal size, Luna's vagina was about 6 inches wide and a foot deep. Now, her huge pussy was a foot and a quarter wide and 22 feet deep, perfect for the huge cock that Toothless was packing. She also did not have breasts at the time, as they typically grow whenever she's pregnant.
Toothless leans his head up and licks around and inside her pussy with his huge tongue, sending shivers down her spine, making her leak juices all over his face and even his neck. She always had a sweet yet funky taste to her that he always loved. Toothless then pulls his tongue away and takes a moment to admire how wet she's gotten, both from stimulation and his saliva. They lock eyes for a moment and knew it was time for the main event.
Luna turns back around and rests her pussy against the tip of Toothless's cock. She slowly pushed down onto the cock, making her pussy lips spread farther than they ever had. Although, proportion wise, it was just like they were normal size, but they didn't care about that for a second.
Luna sits further down on Toothless's cock, making more of it slide into her pussy and making them both moan in ecstasy. Once Luna had reached the halfway point, she stopped for a moment to let herself adjust, which Toothless was fine with. They look into each other's eyes and are reminded of how lucky they are to have found each other all those months ago. And they were even luckier that they both grew at the same time, making their love even more special than ever before. Luna leans in and licks Toothless on the head before continuing her quest to get it all inside her.
Toothless grabs her hips and helps her get further and further down the cock until soon enough, she had the whole cock in, minus the knot which had grown but was not out yet. The knot had grown from the size of a mango to the size of a Catastrophic Quaken, and tonight it was going to feel the insides of Luna's pussy. They both have had sex before this started, so Luna is used to taking Toothless's knot, but now that they were larger, Luna knew to play it a bit safer.
In the meantime, Toothless starts thrusting his hips upwards in an attempt to regain dominance, which Luna accepted. With every thrust, Toothless's huge balls were lifted into the air a bit before he pulls down and they lightly crash against his ass, giving him even more pleasure. Toothless was starting to feel his orgasm building and felt a cool breeze as his knot finally slipped out of his sheath and into the open air. Toothless holds onto Luna's hips tight and slams her against the knot, causing her pussy to spread out more and more until finally his knot slips in, they both roar in pleasure, and his cock erupts with cum inside Luna's pussy. The knot kept the cum inside, so it ended up inflating her stomach a bit as her womb got filled to the breaking point. Luna came as well, making her pussy juice spill out past the knot and onto Toothless's groin.
They both took a moment to bask in each other's bliss as their orgasms died down. Toothless's knot was still preventing them from separating, however he manages to push themselves away from the water and fully onto the island where he then wraps his wings around her and they both fall asleep.
The next morning, they both wake up and find something odd, the island that they slept on seemed bigger than it was last night. Also, the trees that were on the island seemed much taller. This was a bit confusing at first, but they both realized what it meant. "Toothless, are we back to normal size?" Luna asks.
"I-I think so. But how? How did we change back all of a sudden?" Then it hit him. "We had sex."
"No, think about it. We hadn't had sex at least since we started growing right?" Luna thinks about it then nods. "Right, so maybe all that growing was just sexual tension building up and somehow causing us to grow."
"Huh." Luna thinks for a bit. "That makes sense. So, what you're saying is, if we want to stay our normal size…"
"Then we just need to remember to have sex as much as possible."
Luna's eyes widen. "Well, that shouldn't be a problem. Not when I'm married to a stud of a Night Fury."
Toothless nuzzles Luna from that comment. "Come on, let's head home. Oh and if anyone asks, just tell them we found a rock that transformed us back."
Luna nods and she takes him back to The Hidden World. Everyone was thrilled to see that they were back to normal size and luckily didn't question them about the whole magic rock thing. Toothless was able to fit his prosthetic tail back on, meaning he can fly on his own again, and now they make sure to have sex every night to make sure this doesn't happen again.
Alright, thank you for reading this story, I hope you enjoyed it. Puffin, thanks again for the suggestion, I enjoyed writing this.
If you have any other suggestions for stories, make sure to leave a review or PM me. I can't wait to see what else you guys come up with.