[Author's note: the original story of Colin and Karen was told to me as true. The relationship with their aunt and mom is pure fiction]
There is no way I could have predicted the wild week of sex my sister Karen and I had had with our Aunt Julie. My mom invited Julie to stay with us for a week while she and our dad were away. We found out that Mom suspected Karen and I were having sex and wanted Julie to chaperone us, despite the fact that we're both over 18.
The day we almost got caught making love in Karen's room turned out to be one of the best of my life. Aunt Julie was not only cool with us fucking each other, she joined in and taught us a lot about intimacy.
She left the evening before our folks were scheduled to get back, a surprise bonus in my newfound love for my sister.
"I hope Aunt Julie doesn't tell Mom about us," Karen said as we watched Julie drive away.
"Well," I said, "she did promise. I guess we'll see."
"And what about Mom?" Karen said. "She and Aunt Julie were lesbian sisters together!"
"Unbelievable!" I said.
Karen moved up behind me and pressed her body against mine, holding my waist and pulling me close. "It is nice that we get a night and day alone together."
"What should we do?" I asked.
Karen thought for a moment. "How about a bath?"
"A what?"
"A bath. You know, when you put water in a tub and get in?"
"I know what a bath is," I said.
"I want to take a bath together in Mom's big, jetted tub."
"Oh!" I said, starting to picture us both nude. "Not like when we were kids, though."
"Not at all!" Karen said, taking my hand and leading me up the stairs.
Karen and I had grown so close since a kissing game with her best friend Molly turned into us having our first sexual experiences together. Since then, we'd had to take advantage of short times when we were alone. The sex was great, but fast. Now we had all night to explore each other.
Together, we lit candles, filling the bathroom in a soft glow. Karen figured out how to use Mom's speaker and put on some soft music.
"I love you, you know," I said, holding Karen by her shoulders.
"I love you too, Colin," she said, getting up on her toes to kiss me.
As the tub filled with warm water we gently made out. My hands roamed across her back and squeezed her butt cheeks. Her tongue felt nice in my mouth, and I could feel an erection begin.
"Let me take off your clothes," I said, tugging at her shirt.
Karen lifted her arms and let me pull the shirt over her head. She wore a nearly see-through bra underneath, revealing her tiny nipples and dark areola.
"You're so beautiful!" I said, reaching my hands to gently squeeze her breasts.
"Mmm," Karen said.
I bent down.
"Now time for your shorts," I said, pulling the waistband down to reveal a pink thong.
I kissed her mound, and she held my head to her crotch. I pulled down her panties and kissed her tuft of auburn bush on an otherwise bald mound.
"Not too fast," she said quietly.
I stood. "Oh no, I want this to take lots of time!"
Karen reached behind her back and undid her bra. I marveled at her two perfect little breasts.
"Now you," she said, coming close and pulling my shorts and underwear off in one motion.
My cock was semi-hard already and twitched slightly. Karen grasped it and stroked it a little, making me harder and sending warm feelings through my body.
I lifted my hands, and she took off my shirt. Now totally nude, we held hands as we stepped into the inviting water. We sat facing each other and turned on the jets, letting the bubbles wash over our bodies.
"I love how your nipples float above the water," I said.
We drew close and kissed, the sound of the jets mingling with the slurping of our mouths and tongues.
In a few minutes the jets turned off. I leaned back to turn them on again.
"Oh look," Karen said. "Your dick is poking up. Looks good enough to eat!"
"Then why don't you?" I said, putting my hands under my hips to hold myself just above the surface.
Karen leaned over and gently kissed the head of my cock. "It's so squishy!" she said.
"It loves your attention!" I said.
She held my shaft and licked it up and down. Then she opened her mouth wide and put it in. Just in the moments my dick had been out of the water, it had cooled, so the warm wetness of her mouth sent shivers through me.
"Mmm," Karen said. "Tastes so good!"
She started twisting her hand on the base of my cock while sucking up and down. I was getting very turned on.
After a few minutes, she lay back and her pubic mound rose to the surface. I grabbed her butt and held it up so I could put my mouth on her pussy.
"I want you to fuck my pussy with your tongue, Colin," Karen said, pulling my head between her legs.
I went slow, kissing her inner thighs and the top of her mound. She shivered as my lips kissed her labia. I tasted her tangy flavor as my tongue parted those lips.
"Oooh," she murmured, watching my every move.
I licked around her clit, surrounding the little nodule with my tongue and kissing it with my lips. I sucked in gently and Karen gasped.
"Shit!" she said softly.
I licked down her slit and felt her vagina. The taste was much stronger here. I gently pushed my tongue out into her opening. She moaned and began raising and lowering her hips. I stuck out my tongue and made it as hard as I could, shoving it in and out of her.
"Oh, man!" she said, a little louder. "Oh, fuck!"
I sped up, just slightly. Her rhythm matched mine.
"You're going to make me cum, Colin," she said, grunting and moaning.
I withdrew my tongue and kissed her pussy lips. "Not yet, my love. Not yet."
I let her body down and slipped my legs under hers, my dick resting against her mound.
"I, um, I want you to come inside me," Karen said dreamily. "But just rest there, if you can."
"That'll be hard, but I'd love to try!" I said.
I positioned my dick at her lips and felt a wonderful warm tightness envelope my cock as it slid easily inside her pussy. I felt tingles as the base touched her lips. I was all the way in.
"Oh, fuck that feels good," Karen said. "I want to ride you so bad."
"Hold on as long as you can," I said. "It's hard for me too. I want to make you cum with my cock inside you!"