Now this is what we're talking about,” he huffed between heavy breaths. His body was starting to shake. The heat was collecting in his groin, making his dick start to twitch. A sexual energy washed over him, and he started to blush as a small boner popped up in his pants.
“Really, that's what that was about?” he asked in disbelief. He pulled the wasteband of his pants down a little so he could jerk himself off and get out of the cave. His dick was sticking about five inches from his thin, toned body. It wasn't super impressive, but he was a pretty impressive person so his charisma made up for it. He began to stroke up and down his length, urging the blood flow and sending wave after wave of pleasure through his body. His heart started to beat fast, and each pump of blood flowed to his member. He could feel it throbbing under his fingers. Veins were pulsating with blood, becoming thicker and harder than ever before. He could swear his girth had increased by a little bit.
He started to watch his dick closer as he stroked himself, and could see that it was in fact growing more with each flow of blood. He was so hard he couldn't believe his dick wasn't bursting. More and more blood pooled in, and it kept growing in his hand. It pushed outwards, hitting seven inches, and then eight. It expanded, too, until his hand couldn't wrap all the way around it. As it grew bigger and bigger it deepened in color to a cherry red. His veins spiderwebbed up the increasing length and gave him more pleasure and his hand moved over them.
His dick was stretching longer and longer, the tip was twice as big as it used to be. He could see precum dribbling out of it at an impressive rate. He kept stroking as hard as he could, but climax was nowhere in sight.
Every pulse of his heard was like its own orgasm, but no matter what he could not finish. Pulse, growth, pleasure. Pulse, growth, pleasure. He was at ten inches now, twice as long as he was minutes ago. It was still growing. Eleven inches. Every sensation made him moan out in sexual bliss. Twelve inches. A whole foot of thick, red cock in front of him.
“Unh, what is happening...to me,” he said. He couldn't believe that he had grown this big. He had to bite his lip to keep from shouting out. Suddenly, he heard a rip from behind him. His shirt fell to pieces at his feet, and he stopped jerking himself. He looked over his shoulder to see that from his back two big, red scaled wings had grown. He could move them, flap them up and down. He tried flapping them hard once and flew a few feet into the air.
“Woah,” he said in awe. As soon as his feet hit the ground, he fell to his back. He saw his toenails start to sharpen out to a point and darken to a black color. His arches started to ache and he watched as his feet started to lengthen, pushing out from the middle. His toes started to thicken and wrap around his nails, which were more like claws now. They grew bigger, and bigger, breaking his sandals right off his feet. They started to resemble paws more than feet. They shifted in size until he had at least size twenty-two feet. His claws grew long and sharp.
He had now what were very recognizably the giant paws of a dragon instead of human feet. His body looked almost too small for them, until the next surge of energy hit him and he could feel his entire body starting to strain. He watched as his legs pumped full of muscle, becoming hard and thick. They grew longer, and when he stood he could tell he was at lead half a foot taller. His torso started to stretch next, pulling at his abs and making him look like almost too thin until his chest started to barrel out and he could feel his abs bulging out. Soon he was proportional again, but then his muscles build up more. His chest thickened into meaty slabs, his abs became hard as rocks, and his obliques pushed out so that he had a perfect V line down to his massive cock.
Next to grow was his arms, which were like limp noodles on his body now. His shoulders started to round out, becoming thick and strong. His biceps started to fill out. The pulsed and throbbed full of muscle. He flexed them and they formed impressive mounds on top of his arm. His hands started to grow bigger, his fingernails pushing out into black claws like his toenails. His forearm became thick and vascular.
He stood now at eight feet tall with a cock still throbbing hard and getting longer. He had so much girth that he'd need both hands to jerk himself off, and he was at least fifteen inches long now. His body was covered in slabs of lean muscle that made him look like he's spent years of his life working out.
Natsu's pants now strained to keep themselves on his body. He could feel them clinging tightly to his skin. He started to feel woozy as yet another wave on energy hit him. He heard tiny shreds, and looked down to see little red things tearing holes in the fabric. He reached down to poke one, and felt a pressure behind it on his skin. It was growing out of him, and felt like a scale. He saw more of them now popping up along his arms. He could feel the little pinches of them growing more intensely around the base of his wings. Soon, they were spreading rapidly across his whole body, like a coating of hard armor. They grew paler down his chest and stomach, and darker as they reached his hands and paws
Now Natsu stood with a muscular body covered in scales, dragon paws, and wings. Not to mention his throbbing cock that was begging for attention again. He was practicing flexing his different muscles, seeing how they reacted and what strength they now held. The scales would stand up when he flexed, making him look jagged and sharp. When he wasn't flexed, they sat flat and smooth along all the curves and surfaces. He was feeling pretty hot.
He started to feel a discomfort in his mouth, and felt around with his tongue to discover that fangs were growing in and crowding his other teeth. That soon became fixed as his jaw started to push outwards. The feeling of it was like there was immense pressure on the sides of his face. He had to open his mouth to let out a moan. His nose flattened down as it pushed out to form nostrils on top of his snout. The scales grew up his neck and along it. They started to climb up his cheeks, too. On top of his head horns started to grow, spiraling out of his skull and through his pink hair. They were black like his claws.
He started to feel the need to jerk off again, now that he was almost done his transformation. A pool of pre had formed on the ground below him, covering his feet. He started stroking his long member again, taking in the pleasure once more. With both hands, he could feel every vain being passed over. Every small bump sent a shockwave of energy up his spine. As he grew closer to climax, the energy build felt so good. He was moaning out, making loud roars. His leg was kicking, his big paw pounding against the rock below and making the walls shake. He felt his spine start to grow, the energy build up making it buzz and tingle. It began to wear a hold in the back of his pants, and as it got thicker and thicker at the base, eventually ripped them off.
From his spine he was growing a dragon's tale. Spiked spread down the length of his back and along it, the red scales also making their way down the length. As he continued to masturbate, he wagged the tail like a happy puppy. It slammed against the ground, making big dents in the rock below it. He was hunched over, thrusting his hards back with all his might against his cock, trying for the best climax he's ever experienced before. He was forced down to his knees, throwing his head back and sending a small billow of flame up into the air.
His tail extended to it's full length now, and with a tug, sent a shock up his spine and then back down into his cock, which in return erupted with sperm. He shot his jizz feet up into the air, some of it landing on his chest, the rest forming giant pools all along the floor around him. He recognized it as the same milky liquid that was in the cup that he drank from, and that filled the halls of the cave. He kept shooting the sperm, aiming his cock forward a bit so that it went towards the entrance of the chamber. He was making a huge mess of the place, but it felt so good. With each throb of his cock, he let out another jet of dragon cum, making another pool here and another splatter along the wall. By the time he was done and his cock had gone flaccid (still an impressive ten inches hanging below his waist), he had worn himself out of all energy.
He lay there in exhaustion, his own pools of sperm surrounding him, tongue lolled out to the side of his fanged mouth. He definitely was given more power, but he wasn't expecting it to be in this form.