*Be sure to read parts 1-6 before this*
My girl's younger sister came over to swim with us in our pool. My girl doesn't know this, but I met them both at the same time and my first impression was: "if I can't get the one my age, I'll go for the younger one".
They were built quite differently, my girl was shorter and more curvey in all the places most people want there to be curves. Her sister was a little taller and thinner with small breasts. They both hit me in different ways.
Since then, I viewed her as a sister of my own and the feeling went away.
When they both came out to the pool in bikinis I was reminded of why I felt this way early on.
My girl in black, a skull and crossbones on each breast, her cleavage spilling out. Her bottom did a phenomenal job of showing off her shapely ass.
Her sister was in light blue, ties hung down her thighs on either side of her bottom, and her small breasts made her top fit a little loose, but it did the job.
We swam around for a while before settling down and chilling together. I was backed against a corner of the pool, my arms over either side, my girl leaned back against me. Her sister was positioned like me in the nearest corner.
I couldn't help but notice how the water glistened off the sister's pale chest as she leaned back. I watched her breath, the water shimmering with each rise and fall of her chest.
My girl nestled her ass against me and shot me a look when she noticed I was hard.
I was embarrassed until her mouth spread into a grin.
She turned towards me, gave my cock a squeeze with one hand while she pulled me into a quick kiss.
The three of us talked about random things for a bit until her sister made her way over to the ladder to climb out of the pool.
"I'm going to make a drink, anyone want one?" She asked.
We both said we did.
As she got out, her loose top shifted and revealed a pink erect nipple.
My cock twitched against my girl's ass.
"You saw that too, huh?" She asked, turning towards me with a smile.
"Sorry," I said.
"Why?"
"I don't know...it's kind of weird, she's your sister."
She laughed, glancing after her sister to make sure she's out of earshot. "I think we're past weird after everything we've done,"
"True," I laughed. "But still..."
"Look," she said with that devilish look in her eyes, "I had a big hand in convincing you to do that thing with your cousin not long ago. I think it's time I repay the favor."
"What do you mean?"
"That top is loose, her bottom ties at the sides, and she's a lightweight from alcohol. At the least I bet I can get you a good look at her."
I wanted it, but this was weird.
"Did you know she had a huge crush on you when we first started dating. I bet there's still something there."
"I don't know about this. If it goes wrong it could cause problems."
"Relax. I got this. Besides, she hasn't gotten any in a long time, she's been complaining about it."
I felt my face burn. "Just a peek, right?"
"We'll see," she shrugged with her devilish grin.
Her sister came back and handed us our drinks before getting back in the water.
I took a sip, "damn, this is good!"
"Thanks," she giggled.
We talked about more random things while we finished our drinks.
"My turn," my girl said, getting out of the pool to grab a new round drinks.
It was an awkward wait with her sister. I didn't really know what to say and she was acting nervous, which made me nervous too. Maybe there was something there.
My girl returned with the drinks and on my first sip I could tell she made them stronger.
I shot her a look, she returned it with that devilish grin.
We each clumsily climbed on what was basically floating beds with cupholders and a raised back.
I tried not to pay attention to how the water sparkled on their bodies. How their breasts moved when they laughed. How my girl's cleavage spilled from her bikini top.
My girl was right, her sister was a lightweight. After finishing the next drink she was clearly buzzed and having a good time.
My girl tossed her empty plastic cup out of the pool and challenged her sister to try and pull her off her floaty without falling off her own.
The sister grinned and tossed her empty cup as well.
Here we go...
The both straddled their floaties the best they could as they paddled towards each other.
They clashed, their hands locked as they tried to shift each other enough to fall into the water.
The sister gained the advantage and was able to break her hand free and grab my girl by the strap of her top and pull her sideways.
As she fell, I saw her breast was pulled out of her top from her sister pulling the strap.
She resurfaced, sputtering, "best 3 out of five."
The sister agreed, laughing.
When my girl climbed back on her float, her sister almost fell from her own, laughing.
"Your tit's out!" She managed through her laughter.
My girl looked down, surprised.
"You know what?" My girl said through her own laughter.
The sister just laughed harder.
"That's not happening again," she yanked her top the rest of the way off and tossed it out of the pool, laughing.
Her sister looked shocked but kept laughing.
"You both seen them plenty of times," my girl said, still laughing.
"Whatever, just get your ass up here so I can put you down again," the sister said, trying to regain her composure.
I tested my hand with the cup on my lap, trying to hide that I was hard as hell.
They clashed again.
Hands met hands as they fought for leverage.
To my surprise, in their struggle one of the sister's breasts made it's way out of her top.
I couldn't help but stare.
It was small and supple, water glistening as they moved.
My girl won this time, laughing as her sister fell.
She resurfaced, laughing while climbing back on her float. Her breast was still out.
My girl shot me a grin but didn't say anything to her sister.
They clashed again, my eyes were all but locked on the three exposed breasts as they struggled. It took all I had not to touch myself.
My girl grabbed her sister by the strap of her top and yanked her to the side, making her fall.
This time when the sister resurfaced, she noticed and tucked her breast back in her top, her face red.
"You do realize that your tit's been out almost every round, right?" My girl asked, laughing.
"No!" Her sister said, shocked.
"Might as well take your top off too. We've all seen them already and it's a liability in the game." My girl said, giggling.
"No way!" The sister said, still embarrassed.
"It doesn't bother him, I promise," she smiled gesturing towards me.
"Well no shit," the sister laughed. "What guy would? Two topless sisters wrestling in a pool."
"So there ya go, take it off since it's not bothering anyone. One of them will just pop out again anyway in the next round."
"Maybe we should just stop them," she countered.
"Oh, come on, it's fun! Their just tits, and yours are great."
The sister laughed and shot me a sideways glance.
