An almost painful tent had started to rise in your trunks as you stared at your newfound boyfriend, and he knew it.
"You like what you see?" He whispered seductively, leaning toward you and rubbing his tail against your sore dick. You couldn't even get a word out of your mouth, all you could do was squirm. "Good boy." Your boyfriend moaned, cupping a webbed hand around your cheek.
You didn't mind that your boyfriend now had fins and a tail. In fact, you loved it, but it was all still so new. Your once-girlfriend was now a chiseled fish-man whose looks would put a Greek god's to shame, and you wanted his dick.
"Fuck, you're so cute like this." Your boyfriend laughed, stroking your hair and rubbing your cheek. "I can't believe you're such a slut."
You could feel your face getting hotter and your dick getting harder, it was hard to stay focused. Your boyfriend was putting his whole weight onto you at this point, his pecs dwarfing your own. You could feel his new gills erratically flare open and closed, even if he pretended to be confident, you could tell he was still figuring his new body out.
Suddenly, you felt a quick jerk as your swim trunks were torn off. "Sorry babe, I can't wait any longer." He said excitedly. As shocked as you were by your boyfriend's excitement, you weren't going to fight it. Your dick was throbbing, drips of precum floating in the hot tub.
Your fishy boyfriend floated to sit next to you, as well as a merman could sit at least. He attempted to wrap his tail around your legs. "I'm no sea snake." He giggled, wrapping a muscular arm around your now-naked waist and giving a quick peck to your cheek.
You felt like you were going to die from anticipation, the throbbing was getting worse and the head of your dick was starting to swell from all of the blood concentrating.
"Hey," your boyfriend called, using his other hand to lightly guide your head from looking at your dick to his beautiful face, "are you liking having a boyfriend?"
A quick nod was all you could give, which was good enough for him.
"Good boy." Your boyfriend grinned, pulling you closer. "Let me take care of this then."
Your boyfriend's smooth, webbed hand gripped your dick. Even in the water, you swore his hand had been drenched in lube. Before you could figure how that worked though, the merman slowly moved his hand up and down your shaft. As much as you tried to hide it, you couldn't help but moan repeatedly as his slick hand stroked your ever-hardening dick. Your hips bucked and your hands squirmed, but your legs were forced still as his tail tightened; you weren't used to being the one in submission, and your boyfriend was loving every second of it. "You're such a good boy, you're taking this so well..." he said melodically into your ear. Your boyfriend's beautiful voice made you even harder, and as much as you tried to resist finishing so soon, you couldn't resist it. Streams of your seed released into the water as you breathed heavily, still moaning as your boyfriend kissed your neck. "Hey babe, do you like me more like this?" He whispered, and you could only respond with a rapid nod as you leaned your head back to recover from the best handjob you had ever had.
Your boyfriend continued his questioning. "Do you trust me?" Once again, you nodded in response.
You could soon hear your boyfriend giggling. Even if he now had a tail and a dick (although you hadn't seen it since it retracted), you could tell he was still your former girlfriend at heart, and whatever he was going to do, you knew it was just him being silly as he was before. What you didn't expect was his wet fingers entering your mouth, stroking your tongue. A salty taste entered your mouth, and you knew your boyfriend hadn't just fed you your own semen, he had given you a sample of the salt water in the tub.
"Trust me." Your boyfriend moaned. "It's worth it."
A small part of you in the back of your mind wanted to fight what was now going to happen, but the rest of you just sighed in ecstasy. You had never been so aroused by anyone as much as you were by your merman, and you weren't going to lose him by staying a human the rest of your life. This was a sacrifice you knew you had to make.
As much as you wanted this, you were scared, and your boyfriend could tell as he shifted himself to hold you. "Hey, you've got this." He soothed, holding you tightly. "It's okay, it's okay..." He repeatedly said, kissing your neck and shoulders.
Even with the love of your life comforting you, it wasn't going to make your metamorphosis painless, you started shaking uncontrollably. Your boyfriend continued to hold your legs still with his tail, but it was only helping so much. However, you weren't transforming the same way your boyfriend had, your muscles weren't growing and you weren't becoming more masculine. In fact, your upper body wasn't changing. You were still lean with a bit of muscle, but you weren't built like a god, like your boyfriend was. However, it didn't mean you weren't transforming at all.
Your legs felt like they were being cemented together, even if you couldn't see them, you could feel little pinpricks as what you could only assume were your scales were forming on what would soon be your tail. It hurt, there was no denying that, but your boyfriend made it easier, you couldn't even imagine what he was going through when he changed. You winced in pain, and that wincing eventually turned into a scream. The volleyball players in the distance that you had completely forgotten about turned their heads toward you, though none of them luckily ran over.
Eventually, you started to see your former feet, now fins, extend from the security of your boyfriend's coils. They were starting to merge, and you could see a blue tail forming in front of your own eyes. As your extended legs formed a tail, you felt a transformation your boyfriend hadn't received. You could feel your thighs shifting, and to your shock, they were expanding. If you still had an ass, you would have a bubble butt that Minaj would envy, creating a beautiful hourglass figure.
"Holy shit." Your boyfriend gasped, now taking his turn to admire your figure. "Holyshitholyshitholyshit, jackpot!" He laughed, fondling your curves as your transformation neared completion with the formation of your gills along your pectorals. His primal excitement led to him releasing your tail, allowing you to see your long blue tail. Your gills flared excitedly, moaning softly as your boyfriend massaged your newfound love handles.
There was one thing left unchanged, and it was your dick, but you knew that wouldn't be the case for much longer as the scales approached one of your only remnants of humanity in your lower body. Even though you had just experienced one of the best orgasms of your life minutes prior, your dick was ready for action, and you needed to give yourself some pleasure. You weren't sure what had happened to your boyfriend's dick since he had gained his tail, and if this was the last time you got to see it, you wanted to make sure you enjoyed it.
One glance at your hands revealed that you had the same webbing between the fingers that your boyfriend had, you could feel some sort of lubricant on your hands, which you used to grasp your dick and start stroking, your tail flopping with pleasure. Jerking off this time didn't feel like a desire, it felt like a necessity, as if you needed to rid your body of any remaining human seed. You couldn't have been going for more than two or three minutes, before you reached completion once again. "You're going great," your boyfriend soothed, "you're almost done."
Releasing ropes upon ropes of semen, your dick slowly descended into your tail. You couldn't tell what was really happening, but you could tell that your dick was changing. You weren't sure what it meant, but you could tell it was still there. Thank god.
Your transformation was complete. You were a merman.
"Oh my god." Your boyfriend gasped, stopping his obsession with your curves. "You're so fucking beautiful."
You didn't know what to say, you had assumed that you would have grown as muscular as your boyfriend, but you were instead smaller than he was, and you now wanted him to call you beautiful, and your boyfriend could tell so with your reddening face. He leaned forward, taking a hold of your shoulders and pulling you into a kiss. After everything, this felt right. Your love held you close, your tails rubbing against each other and massaging each other's muscles. It wasn't long until you felt something stirring though.
To be exact, something stirring where your dick once was. Pushing your boyfriend away, you winced as you looked down at your tail, breathing heavily as something alien emerged. It felt foreign, as a slit slowly opened, and veiny tentacle-esque appendage that tapered at the top squirmed around, catching both of your attention. That was your dick, it was small, big enough to serve its purpose, but you would have appreciated something larger.
"I shouldn't be turned on right now." Your boyfriend claimed, exasperated. After he said that, he winced, sensing his own dick of sorts emerge from his slit. "Fuck! This feels so weird."
Your boyfriend had a dick just likes yours', it squirmed around awkwardly, but it was also much larger than yours'. Both of you looked at each other through labored breaths, it wasn't long before the dicks seemed to be attempting to reach each other. "What the fuck." Your boyfriend remarked, somewhat laughing. "With that dick and those hips, you're a total bottom."
You huffed at that remark, but couldn't resist your boyfriend's laughing. "Come on, you know I'm messing with you." He pulled himself toward you again. "Shall we continue?"
You weren't going to say no, and you quickly began kissing your boyfriend again, eagerly frotting and moaning. Your boyfriend laid on top of you, his big dick seemed like it was searching for something, like it had a mind of its own. You didn't care though, you just wanted this moment to last forever. Not too much earlier, you were just boyfriend and girlfriend, looking forward to some time in the hot tub, now you were merman boyfriends, and you loved it.
"Babe, what is that?"
You broke out of your trance when you suddenly felt another foreign experience. Looking down past your boyfriend's chiseled pecs and abs, you could see your dick pulsing excitedly, while your boyfriend's dick was missing. Or, at least out of view.
"Holy shit, we have holes."
Your boyfriend was inside of you.
You felt weird, involuntarily clenching around your boyfriend's dick as it continued to squirm lightly inside your entrance right below your own dick. "What do I do?" Your boyfriend asked.
There were no words to reply with, you just started to whine and try to thrust your boyfriend's dick further into you.
"Holy shit, bratty bottom much?" Your boyfriend smirked, cupping your hips as you held him, continuing to try and get him to enter you further. Any semblance of heterosexuality was long gone, you just wanted dick. Fish dick. "Get ready, gorgeous."
You moaned loudly as your boyfriend's dick went further into your body. You had no experiences with human dicks before, but you could already tell that merman dick was much better. It squirmed around, looking to pleasure itself as much as possible. "Fuck, this is amazing!" Your boyfriend exclaimed.
Your own dick remained on the outside, rubbing against your boyfriend's abs. It pulsed harder and harder, precum dripping as your boyfriend drilled himself harder and harder into your hole, until one hit particularly felt great.
Throwing your head back in ecstasy, you cried in joy as his dick hit a particularly deep area. "I think we found your prostate." Your boyfriend teased, focusing on that area. "Holy shit, you're suck a slut."
Every hit made you feel light-headed, fireworks were going on in your mind as the tentacle inside of you pulsed, stretching you out on the inside, while your boyfriend got gripped even tighter. "Fuck," he gasped, "I'm almost there."
Your boyfriend started going even quicker, thrashing his tail and splashing water out of the hot tub. He dug his fingers deeper into the fat of your hips, making you feel even more pleasured. "I'm... I'm cumming!" Your boyfriend exclaimed, shooting ropes into your body, causing you to come as well, making a mess on your boyfriend's abs.
It went on for several minutes for both of you to finish. "Holy shit... that was amazing." Your boyfriend gasped, scraping a little of your semen off of his abs and licking it off his fingers. "Salty." He winked.
You were too weak to respond, falling below the water to catch your breath. Your boyfriend had came inside of you, and it felt great. You weren't alone for long, before your boyfriend went below the water to lay beside you. Your dicks, while limp, were still recovering before they could re-enter their slits. It had only been an hour or so since the transformation, but it felt like it had been days, and you were looking forward to your next time together.
"I love you." Your boyfriend mouthed below the water, kissing your forehead and holding you close. You were his, and he was yours'.