Kat, my wife's little sister, sat on the couch in her red pajamas, remote in hand and a bowl of popcorn nearby. Her top was unbuttoned except for the last one, thus exposing her red satin bra. I could imagine her panties were of a matching color.

It was movie night, and we were alone this time. It was usually the four of us watching a superhero movie as we were all comic book nerds. My wife, Julie, was called in for a double shift at the ER. She was the head nurse. Lee, Kat’s husband, had his flight back home delayed until the next day.

Kat was only two years younger than Julie. Kat was a third-grade teacher. She was brunette with long straight hair and stood 5'-4". She worked out a lot and was very fit. She had smallish breasts and a nice, firm, shapely ass.

My wife, Julie, had the same facial features: big brown eyes, a firm chin, and sexy cheekbones. She kept her red hair short, just barely to her shoulders. Her breasts were heavy and full at 38C. Her ass was firm and shapely, like Kat's. We would have sex about four days a week. We fucked hard and heavy and also slow and tender. She loved to fully take my thick eight-inch cock in her mouth and swallow my salty gift. She would scream when I ate her out. We did not have anal sex or have any desire to.

Kat and Lee seemed to be madly in love, but I know nothing about their sex lives. If the girls confided in each other about their sex lives, they kept it to themselves.

So, I am thirty-two, Julie is thirty, and we have been married for eight years. Kat, of course, was twenty-eight, and Lee was thirty-four. They have been married for five years.

I am a structural engineer. I have curly brown hair and stand 6'-2" tall. I have a swimmer’s body with broad shoulders and muscular features. I swam for the US Olympic team, and I won two individual gold medals and three team gold medals.

I had had no sexual desires or inclinations towards Kat. Kat, on the other hand, is a constant flirt and embarrassed me every chance she had. She and Julie laughed at how red I would get when they talked raunchily, especially if we were in public.

I sat at the other end of the couch in my pajamas. This was the attire we all wore on movie night, since Kat and Lee usually spent the night at our house, as we stayed up late, and we lived an hour and a half apart.

Kat patted the couch seat next to her, signaling me to move closer. "We can't share popcorn if you are sitting way over there," she laughed. I scooted over next to her, and in doing so, the fly opening in my pajamas opened up without me noticing. Kat did notice, though. She cleared her throat, and when I looked at her, she motioned with her eyes and head towards my lap. When I looked down, my five-inch flaccid cock was lying outside my pajamas on my thigh.

I turned red and tucked it back in. Kat giggled and said, "You know Julie has shown me pictures of your cock before. Your soft cock is longer and thicker than Lee's. Here, if it makes you feel better, look at my titties." She took off her top and unhooked her bra.

Kat's breasts were perfect, firm mounds with small dark areolas that had fat, stubby nipples in the center. My cock twitched, and Kat noticed. "Pull out your cock and stroke it," Kat panted. I pulled out my smooth cock, and I wagged it in the air. Our eyes locked in a daring stare. My hand wrapped around the base, and I slowly stroked. Kat broke the stare off and glanced down at my cock. I watched her chest turn pink and her nipples harden.

As I stroked my cock, it grew to its full eight inches. Kat seductively bit her bottom lip and shifted in her seat. I grabbed a handful of popcorn and stuffed my mouth as I stroked my cock a little faster. "Take off your bottoms and spread your legs," I commanded.

Kat lifted her ass off the couch and took off her pajama bottoms. She wore a bright pink thong. "Those as well," I said. Kat let out a big breath, and her arms were shaking as she slipped her thong off. Her brown bush was trimmed into a wide landing strip. She slowly spread her legs and watched my eyes as she opened up for me. "Finger yourself and play with your tits," I whispered.

Kat squeezed her right tit and twisted her nipple. Her other hand spread her folds and ran two fingers up and down her valley. Her pussy lips were much darker and much longer than her sister’s. She sank two fingers deep into her cunt. She worked them in and out, then slid them up her valley and over her pea-sized clit, then back into her pink cavern.

Kat was vigorously masturbating and moaning loudly. She was close, and so was I. I stood up in front of her, wanking my cock hard while aiming the head at her perfect tits. Kat arched forward and let out a scream. Her nectar flooded the couch. This set me off, and I also arched forward and blasted her chest and tits with several ropes of cum.

I plopped down on the couch, spilling the popcorn everywhere. We both lay back exhausted after a thirty-minute blast of energy. We both thought we were done and had gone as far as we were going to go. I got up and put my cock back into my pajamas. I threw Kat a towel to wipe my cum off her chest and to dry her pussy.

I went off to my bed. I washed my hands and brushed my teeth, then climbed under the covers. Kat walked in still naked. She looked stunning. "I'm not done with that big cock of yours," she announced. She pulled off the covers and jerked my pajama bottoms off. My cock sprang up hard as can be. She crawled with her head between my legs. She wrapped her hand around the base of my cock and moaned, "Oh Gawd! Your dick is big."

She licked around the frenulum, tasting the residue of my cum from wanking. Her lips pushed down over my shaft and went halfway down. This was the length she was used to. The extra girth didn't seem to affect her performance yet. She tried a few more inches, but when the head hit her uvula, she coughed and gagged. Six inches is all she could take, but that was more than enough. She had a different sucking technique than her sister, and although Julie could take all of me, Kat gave a much better blow job. She was enthusiastic and rigorously sucked. When her brown eyes locked onto mine, I lost it. Without warning, I filled her mouth with more cum than she could handle. It poured out all over her chin and dripped down her neck.

I placed Kat on the edge of the bed and spread her thighs apart. Her aroma wafted into my nose, and she smelled fresh and sexy. I ran my tongue over her dark, long pussy lips and sucked them into my mouth. My tongue darted into her pink tunnel, scooping out her sweet nectar. Her moans were sexy, and they guided my tongue where it needed to be. Her soft thighs gently squeezed my face. I couldn't resist licking her asshole to see what her reaction would be, as Julie does not care for anything touching her anus. Kat moaned, "Yes, you nasty boy, lick my ass, eat my ass."

Jesus Christ, she is so hot. My tongue pushed deep into her ass. It was my first time, and the pungent taste was a turn on.

I moved to her clit after eating her ass. Her clit was pea-sized and out in the open. Kat pulled my hair and screamed as I sucked and licked her clit. Her thighs clamped tightly around my head, and her entire body shuddered. She arched up and flooded my mouth with her white creamy nectar.

We lay side by side, both breathing hard. We had yet to kiss. If I kissed her, then that meant we were going to fuck. We didn't want it to go that far, as we both cherish our spouses.

Kat moved towards me, and we locked eyes once again. Her soft lips pressed against mine. We both moaned. She slipped her tongue into my mouth, and I slipped mine into hers. Still kissing, she rolled on top of me and straddled my waist. Her wet pussy pressed against my stomach. She broke the kiss off and panted, "I need your big cock inside me. I want you to stretch me and go deeper than anyone has. Please, Mac, I need it."

She grabbed my cock and lifted. She placed my big purple head at her pink entrance. She gasped, and her eyes rolled up in her head as she sank onto my cock. She was so fucking tight. I sucked her dangling little titties. "Oh God, oh God! I feel you so deep, Mac, fuck me, fuck me hard," she moaned.

She sat all the way down. Her eyes were closed, but her mouth was gaping open. Her breasts were vibrating. She was having a long, intense orgasm. She opened her eyes wide and blurted, "I have never had such an intense orgasm as that before."

She lifted about six inches and plopped back down. She fucked me hard and fast. I thrust up into her as she plopped down. We were loud and animalistic. She came multiple times. Her tight velvet walls felt like heaven to me. I was ready to fill up my wife's sister's pussy with my creamy seed. "Oh, fuck Kat! You feel so good. I'm cumming, shit, I'm cumming," I growled. I unloaded deep inside Kat's cunt. My warmth spread inside her, and I kept blasting rope after rope. Kat closed her eyes and moaned as she savored the feel of my warm seed.

I hadn’t finished with my sister-in-law. I grabbed her and placed her on all fours. I was about to do to my wife's sister what my wife would never let me do to her. My cock pushed into Kat's starfish. She groaned with delight. "Fuck you are big! Take my ass. Claim it as yours."

My shaft pushed her smooth colon walls wide. She felt good as I impaled her. She grunted with every thrust. I never met a woman who loved being fucked in the ass as much as Kat. Her legs were shaking, and she was panting as she was having an orgasm while being fucked in the ass.

It didn't take me long to unleash another batch of my salty seed into her ass. When I pulled out, I watched her gaping hole pulse and push out my cum. It was amazing.

We fell asleep in each other's arms. Kat and I never would have sex again. We never told our spouses about that special movie and popcorn night, but we both cherished it in our hearts.