Author's Note: All characters in this account are of legal age and no sex acts are conducted with any persons under 18. All rights reserved.
I was still naked when the sun came up, shining through the sliding glass door. I also had a normal morning woody, compounded by the sensations of Jenny snuggled naked against me, and Chris having played with me last night without giving me an opportunity to get off. I could feel my dick pressed against Jenny's ass and couldn't help myself from gently moving myself away long enough to point my engorged head at her pussy lips. I felt my head spread her lips and slowly sink into her depths as I lay spooned against her. She moaned softly and pushed back, trying to push me deeper, enjoying the feeling of my dick sliding slowly into her either in her sleep or awake. I slowly rocked myself, trying to stay quiet as I worked my shaft in and out of her hot wet confines a couple short inches. She moaned softly again, making me wonder if she was still asleep. As quietly as I could I kept rocking my hips, working my engorged shaft in and out of her sexy pussy, enjoying the sensations as well as the quietness of the interlude, instead of the rushed pushiness that seemed to dominate our awake encounters.
"That's a nice way to wake up." She whispered, reaching behind herself to pull my ass with her hand. She moved her hand from my ass, found my hand resting on her hip and gently pulled it down between her legs, a clear request to play with her clit while I stroked in and out of her. I let my finger slip down between her lips to draw some of her own juices up to her clit and then gently teased it as I pushed slowly in and out of her, working both of us toward the inevitable conclusion.
I froze when I hear one of the sliding bedroom doors, my dick still shoved deep into Jenny's pussy. I held her from moving when I realized that it was Aunt Mary's room that had opened, and she was padding bare foot to the boat's kitchen. I looked toward her, catching a glimpse of her in a semi-sheer nightgown, as she fussed with starting the houseboats generator and then moved to get the coffee maker started. I hoped the noise of the generator would mask the sounds of Jenny and I as I went back to slowly stroking, craning my neck to watch Aunt Mary in the kitchen, worried she might see us. She leaned against the counter, watching the coffee maker while Jenny and I gently, softly, quietly continued to rock into each other.
I froze again and squeezed Jenny against me to coax her to stop as Aunt Mary pushed away from the counter. She walked past us as we pretended to be asleep, walking to the sliding glass door only a few feet from the end of our sofa bed. She stood looking out over the lake, the sun shining in through the window, through her thin gown, silhouetting her body as she stood there. I watched her as Jenny forced me to ease my grip on her and go back to slowly fucking. She rocked slowly and quietly, my body encouraging me to do the same, the two of us taking what felt like long minutes to get back to the level of excitement we'd been at before Aunt Mary walked by. As I watched her standing in front of the window, I could see the silhouette of one hand and slide between her legs, her fingers teasing her pussy lips. She did something in front of her that pulled the hem of the gown up in front, the hem in the back sliding up slightly as well. The already short back of the gown pulled up over her ass far enough that I had a clear view of her pussy and fingers as she stood looking out. She leaned her head against the glass as her fingers slowly stroked her pussy lips, her fingers dipping wetly into her pussy, while I lay behind Jenny, sliding my cock in and out of her pussy and watching her. I wondered if she even realized that she was showing me her pussy, as she leaned against the door and stifled a quiet moan.
Aunt Mary's fingers pushed back and into her tunnel, pushing in and out slowly, almost in sync with my strokes into Jenny. I could hear the soft squish of her fingers pushing into her and my mind started to imagine me standing behind her, pushing my cock in and out of her pussy instead of her fingers, as I drove my dick in and out of my sister. The hot wet depths of Jenny coaxed me closer and closer to climax while Jenny softly moaned, her pussy starting to squeeze and spasm around me as she tried to climax as silently as she could.
"Oh fuck." I heard Aunt Mary whisper as she appeared to climax in front of me, causing my own climax to peak. I grunted softly as I jammed my cock into my sister's already climaxing pussy, spurting a massive gush into her. Over and over I jerked, unable to stay completely silent as my body sent spurt after spurt into her. Aunt Mary stood silently for several seconds with her fingers in her pussy and then slowly drew them out of herself, dropping her nightgown to cover herself again, She pushed away from the window, turned to walk past us to the kitchen again without looking down at us. I quickly closed my eyes and did my best to control my body as she walked across the room into the kitchen.
Jenny slowly moved one hand to my hip and gently stroked my skin while my cock, still buried in her, occasionally twitched, my hardon slowly starting to fade.
I lay there silently, listening to the gentle hum of the generator and the sounds of Aunt Mary pouring a cup of coffee while my softening cock slipped from my sister's pussy. Aunt Mary walked past again, this time opening the sliding glass door and walking out. I could hear her climb the stairs to the rooftop deck and settle into a chair.
Jenny rolled over to face me and gave me a soft kiss. "I can't believe we did that without her catching us." She whispered.
"Me either." I answered, pulling the sheets off of us. "We better put something on before anyone else wakes up."
"Uh huh," she agreed, sitting up to look for her sleep shirt while I looked for my shorts. We both dressed and then lay back down to pretend to be asleep a while longer, Jenny curled up against me, pulling one of my hands around her to cup her tit through the thin shirt.
I heard the girls get up and decided that we should do the same. I gave Jenny a soft kiss on the back of the neck before rolling away and climbing from under the covers.
"Morning sleepy head." Dee said with a grin as she pulled off her shirt, leaving her naked. "I'm gonna go get a shower. Wanna help?" she asked as she tossed her sleep shirt on the bed. She bent over, sticking her now bare ass out at me as she dug in her duffel bag. She wiggled her ass back and forth at me, making sure I had a good view of her full round pussy lips and the inner labia protruding. Her lips glistened with wetness as she remained bent over for me to stare at. She finally pulled a towel from her bag and stood up, turning to face me as she wrapped the towel around herself, giving me one last look at her big round tits before covering them.
About that time Uncle Russel stepped out of their bedroom. "You kids should probably use the shower on the stern. We have a limited supply of fresh water and I know how long you girls can spend in a shower."
"But that's lake water!" Chris complained from where she sat in bed. "Not to mention that anyone can see you out there."
"Actually it's filtered lake water. But if you prefer you can just go wash in the lake. And as far as being seen, if you wear one of those little bikinis you two are so fond of, there isn't a whole hell of a lot that won't get washed anyway." He responded before walking toward the bathroom.
Completely exposed isn't quite what I'd call it. I'd seen the small shower cubicle under the stairs heading up to the upper deck. It was enclosed on three sides, one by the stairs, one by the back of the cabin and the third by a partition between the two. Only one side was open, the side that faced inward toward the center of the boat. If you walked out the back sliding door you had to walk right past the little shower stall, which was probably designed to let you shower off sand and the like after swimming.
"I don't mind." Dee said quickly, stepping toward me. She hooked a finger in the front of my shorts and tugged. "Come on. You can wash my back and I'll wash yours. But you probably better take these off. Don't want to get them wet, do you?"
"But the girls...?"
She turned to look at me, still backing toward the door, drawing me along by the waistband of my shorts. "You are soooo funny!" she giggled. "Not like we haven't all seen your cock already."
"SHHHHH!" I hissed quickly, not wanting to advertise what had happened the day before upstairs. "But...Aunt Mary?"
"I'm sure she'll enjoy the view every bit as much as I did yesterday." She whispered as she reached the glass door with her butt. She reached behind her, slid the door open and pulled me out onto the rear deck. "Now, about these shorts." She said, stepping toward me and moving her hands to my hips, pushing my shorts down and letting them slide down my legs. She reached for my cock with one hand and the towel around her with the other. She hung the towel on a little hook on the side of the stairs while she played with my soft cock. She squatted down to pick up my shorts and toss them toward one of the bench seats on the stern. "You know. Smells like someone's been playing already today." She said quietly, switching hands and lifting her other hand to her nose and sniffing it. "Yep, that's what I thought. Smells of pussy." She said as she stood up in front of me.
"I didn't...We didn't. I mean..."
"Don't worry." She said quietly. "I won't tell anyone you're fucking your sister. It'll be our secret."
"How do you know it was Jenny?"
