“Is that what the slutty swimsuit is about?” I asked. “Trying to butter me up so you could watch?” Damn, that was kinda hot. I had a raging erection. Luckily, the hot tub had bubble jets, so nothing beneath the surface was visible.
“I promise I won’t tell mom or dad. And it won’t be like you’ll be sticking your dick in me. I just want to see how it goes. Maybe learn a trick or two for when I find myself a man.” She was nearly crying.
“Of course you can.” Courtney told her.
“WHAT?!” I blurted out.
“Oh, come on. It won’t hurt anything.” Courtney insisted. “Besides, you were lamenting that you couldn’t have fun with me in front of your sister. Now you get the best of both worlds.”
“I knew I liked her.” Cindy glowed.
I almost objected, but Courtney started working my dick with her hand under the water. She knew what she was doing and she knew what it did to me.
“This is so unfair,” I moaned. “Why in front of my sister?”
“Because she needs it.” Courtney informed me, a familiar look in her eye.
“Not the same.” I told her.
“Exactly the same.” She told me, moving to my balls.
“Fuck, fine!” I gasped
“You mean it?” Cindy squealed in delight.
“Yeah, but we’d better move quick. Mom won’t like it if we’re late for dinner.” And I stepped out of the pool.
Cindy’s eyes got wide as my swim trunks draped on my erect manhood.
“That helps with getting a hot piece of ass.” Courtney told her.
“Fuck, it’s huge!” Cindy gasped.
“It’s fantastic.” Courtney laughed.
We toweled off and went inside.
The master bedroom was set up with clean sheets and had some protective coverings on. Apparently, most people renting this airbnb weren’t using it for business trips…
“Fair is fair, though.” Courtney informed her, “You see us naked, we see you naked.”
“I-” I started and Courtney shushed me.
“Na-Naked?” Cindy stuttered.
“Honey, you are basically naked as is. Cute asshole by the way, saw it while you were toweling your legs off.” Courtney informed her.
Cindy’s face was beet red. I thought for a minute she’d back out. But she steeled herself, her face still beet red, and took off her string thong bottoms. Her pussy was cute, kinda puffy from her arousal, and a lovely pink. Then she removed the poor excuse for a top she was wearing. Her nipples where large for her breast size, explaining why they were so easily visible. Her areolas were barely large enough to contain her nipples.
“There, was that so hard?” Courtney asked, slipping her own top off and sliding out of her bottoms.
Cindy nodded, “It took me five minutes to get the courage to come out there in that… I didn’t think I’d have to get naked…”
“You’ll get used to it. Being naked in front of a boy.” Courtney assured her, and she took the pleasure of removing my swim trunks.
Cindy’s eyes were glued to my cock.
“Is this the first one you’ve seen in real life?” Courtney asked, gently stroking me.
Cindy nodded, unable to speak.
“If Tom wasn’t your brother… nevermind.” Courtney murmured. “Tom, show her how a man pleases a woman.” And she laid down on the bed.
I dove into her to distract from my naked sister. I wasn’t supposed to want to fuck her. I blamed Courtney. Courtney was the one who got me in a bedroom, naked, with my naked, horny sister. Courtney also had opened me up to having sex with a variety of women. But I couldn’t be angry with her. And I couldn’t say it wasn’t hot.
I started kissing Courtney passionately, then moved to her neck and began groping her tits.
“Oh, fuck! He’s wound up tight!” Courtney moaned as I mauled her tits and sucked on her neck. I had to be light on her neck though, her coming back with a hickey would give away we did something with my sister here.
“Oh god!” Courtney moaned as my hand dropped between her legs and I started sucking on her open breast. Courtney’s legs spread extra wide, probably to give Cindy a view. I was thumbing her clit, my two fingers pumping in and out of her tunnel, massaging her g-spot. It only took a minute of this for Courtney to orgasm. It was a good thing that there was a protective cover on the bed, because she squirted like a geyser. “Fuck! I’m cumming!” She gasped. “I love it when you make me squirt!”
I moved into position, and I heard Cindy gasp behind me as I pointed my penis right at Courtney’s opening, and slid inside.
“Fuuuuuuuck!” Courtney moaned, “Now… Cindy… hopefully… your… first… time… will… be… more…. Gentle… but… once… you’ve… done… it… a… a couple… of times… it… feels… so… good… to… just… get… pounded!” Courtney exclaimed.
It made it impossible not to think about my naked sister, and I glanced over at her. She was standing there, rubbing her inner thighs together and massaging the mounds of her breasts. Her eyes met mine as she panted, and it pushed me over the edge. I plunged deep into Courtney’s hole and exploded.
My quickies on the plane had done little to drain my balls, but this time I emptied into Courtney, I must have squirted ten times. As my first squirt hit her cervix, Courtney came again, squirting a second wave of her clear ejaculate over my hips.
I pulled out and flopped next to her.
“Come see what he did to me.” Courtney instructed my sister.
Cindy didn’t need told twice.
Courtney pulled her pussy open and pushed my sperm out for my sister to watch.
“That looked like you really enjoyed it.” Cindy whispered.
“Did you need to rub one out?” Courtney asked, seeing her still grinding her legs together.
“I’m trying!” She complained, “Everyone acts like it is easy, but I can never get it to feel how everyone describes!”
Courtney and I exchanged a glance.
“This… This isn’t how you do it… is it?” Cindy hung her head mortified.
“Have none of your friends told you how to masterbate? I know sex ed is worthless, but no one told you?” I asked her.
“No. I mean… they might have… if I was willing to admit I didn’t know what I was doing….” Cindy confessed.
“You didn’t find anything on the internet?” I presseed.
“You loser! You’re the one that helped dad set up the internet filtering! I couldn’t search anything!” She snapped at me.
“… That filter is so easy to get around…” I laughed.
“Fuck you, just tell me how to make this tingling between my legs stop!” Cindy begged.
“Come up here on the bed.” Courtney told her.
Cindy obeyed.
“Now open your legs.” Courtney told her.
Cindy hesitated a moment, then obeyed.
“Tom, show her where her clitoris is.” Courtney told me, her eyes glinting wickedly.
I stared at her, and she met my gaze. This was a line I couldn’t come back across. Lots of siblings saw each other naked at some point, but this would be me touching her… sexually.
“Please, Tom.” Cindy begged.
I caved. I reached down and felt her folds.
“This is your urethra, where you pee from. Just above it here is your clitoris.” I informed her, I grabbed her hand and led it to her to feel herself.
“Oh fuck, that feels good.” She moaned, her eyes closing.
“Now rub little circles on your clitoris.” I told her.
She obeyed with vigor.
“Oh, it… it’s building….” She gasped, her eyes clenching as she rubbed faster. “OH! FUCK!!!” She gasped and her body spasmed lightly in her first orgasm.
“Fuck, that felt so good! Thank you, you two!” She cried, tears running down her face as she pulled us both close.
It was a sweet action, with sweet intentions… but Cindy basically stuck my face on her boob. Courtney was on the other one. She eyed it thoughtfully and thought better of whatever she was thinking.
Cindy abruptly realized that she was naked and holding her brother’s face, and his girlfriend’s face, inches from her naked nipples.
“Oh, I’m so sorry.” She gasped, releasing us and covering her tits with her hands.
“Oh, don’t worry about it. I am just glad we were able to help you.” Courtney laughed, “I trust you found it… educational?”
“Um, Yeah. I learned a lot.” Cindy stuttered. Now that her horniness was satisfied, what she had just done seemed to settle in. Her face was flaming, and she was trying to cover her important bits.
“Shall we get dressed?” I suggested.
Cindy nodded emphatically, and Courtney laughed.
Cindy ran from the room to the bathroom to change and Courtney and I got dressed.