Getting frisky with my gf while her sister sleeps next to us [MF]

This just happened over the weekend, and I’m still mildly in shock.

So, a bit of context: my (M22) gf (F21) and her family where taking a trip to the beach over the weekend and invited me along. There where only two rooms, a master bedroom which my inlaws shared, an a room with two bunk beds in which we sleept. The arrangement, at least to the eyes of her parents, was that my gf would sleep on the top bunk, I would sleep underneath, and my gf’s sister (F18) would sleep on the bottom bunk next to ours. My sister in law is very chill about us, so my gf told her she would sneak down to my bunk during the night, which she agreed with no issues whatsoever.

Now a small description of them: my gf is absolutely stunning: brownish-blond hair, hazle eyes, slim figure, small breasts, petite waist, huge ass, and slim legs. She is 5’2, barely 100lbs, and super kinky. My gf’s sister is pretty much her clone, except she is a bit taller (5’4), with a smaller ass and less waist line.

Now back to the story.

Night falls, my in-laws are fast asleep by now, and my gf climbs down to the bottom bunk. She closes and locks the door, and gets in bed with me. Her sister is still deep asleep (they have a gift for sleeping through almost everything.) My gf is wearing a long sleeping shirt with nothing underneath. I hadn’t noticed this until she turns to face away from me (towards her sister) so that I could spoon her, leaving her ass covered by only a frail bit of shirt exposed. Now, I’m wearing only boxers and shorts and I’m getting hard; but thinking that she doesn’t want to do anything because of her sister being in the same room I just try to remove my hips a bit. She, however, follows them as if she was glued to my dick and starts to gently move her ass up and down. By now I carasing her breasts, her pointy and perky chest, with one hand and her ass with another. She is still wearing that sleeping shirt. I test my luck by teasing her with a finger and she just digs her nails into me and continues to rock her perfect ass. I whisper for her to be quiet and she just knods slowly and gently while buring her mouth in my arm. I slowly penetrate her with a single finger and I can feel her juices flowing. With my middle finger still in her I take my thumb and begin to tease her buthole and I can feel her shaking in ecstasy. This goes on for a while until she orgasms and I feel her juices flowing through my hand.

Without a second of thought she turns around, puts me on my back, and crawls into the covers. She takes off my underwear and shorts in a single motion and starts going down on my cock, I take her head in one hand and force it deep into her throat as she happily obliges. While this is happening I turn my sight slightly and see the faint outline of a bump on her sisters bed. My eyes adjust to the dim brightness from the moonlight and I start to see whats going on: her sister has her eyes fixed on our bed, legs bent underneath her covers and both hands inside of them. I can only presume whats going on, but I can tell she hasn’t noticed me staring yet. This almost brings me over the edge, but I stop myself before I spoil one of the greatest moments of my life.

I bring my gf’s head up from underneath the covers as she moans from not letting her finish me. I tell her to get back to the same position we where before and go down on her. Now she’s facing her sister, I’m beneath the covers and can’t tell what’s going on, but still decide to put on a show. I take her pussy in my mouth as I stroll my fingers all over her legs and ass. Then, in a single motion so that she doesn’t expect it I turn my attention from her lips to her ass, she lets out a moan that I manage to muffle with a hand. She starts to bite, hard, as I continue to eat her up. I move up again, towards the same spooning position we where before, and whisper for her to ne quiet. She knows what is going to happend and takes my cock with confidence in her hand and guides it into her pussy. I begin to move slowly as she thrusts her hips towards me. I take this moment to look to her sisters bed and I see her eyes staring straight as me, she has turned on her side, still with one hand beneath the covers, she takes her other hand and, without breaking eye contact, licks index finger and brings it to her chest beneath her shirt. I proceed to do the same with her sister (who has her eyes closed and is thus oblivious to this.)

My gf’s sister then takes that same hand off of her, and uses it to take of her shirt and expose her tiny, perky, and perfect breasts. She licks ger thumb, motions with her eyes and begins to trace over her bare chest with her thumb. When she gets to her hips I notice the sheet is no longer there, and she is completly nude. One of her hands is still going at it gently but her other had disapeared. I look up again and see her shushing me with her finger. She takes her thumb and sticks it in her mouth again, takes it out, and with a teasing smile sticks it behind her back. I see the moment where her eyes close and her body jerks towards the edge of the bed and catch the hint, I take my cock out of her sisters pussy and stick it into her ass. My gf lets out another muffled moan and pulls me close to her. She whispers for me to please cum inside her and I just lost it. I look at her sister and she just nods. I take three more deep pumps, our eyes locked, and cum deep inside her. I feel the juices from my gf flowing at the same time in my legs and I see my gf’s sister spasm in joy.

My gf turns around, whispers that it was excelent, and falls asleep almost instantly, I look over to her sisters bed and see her wink at me, take the covers from the foot of the bed up, cover herself and turn around to sleep.

Source: reddit.com/r/gonewildstories/comments/bgjr9u/getting_frisky_with_my_gf_while_her_sister_sleeps