My wife and I have been together for over 10 years. Two years into our dating relationship I was visiting her for the weekend at her parents house. We were long distance at the time. On this specific trip her sister seemed to be much more grown up. Prettier, curvier and her boobs just seemed to have grown out of nowhere. We had always been very friendly towards each other. Quick to hug and quick to laugh at each other. But now I was noticing how beautiful she was too. On that Saturday we all decided to use the neighbors hot tub and were enjoying the hot water when her friends came looking for her. They came up to the hot tub and she bent over the side of the elevated platform to talk down to them. Her butt pointing straight at me, with the bikini bottoms going up her crack. Her pussy was now staring right at me only covered by a thin piece of fabric and I got hard. I looked at my girlfriend and gave her a awkward grin and she laughed at me thinking nothing of it.
That night her whole family and I had a great time at dinner and playing games. At the end she went up to bed and my girlfriend and stayed downstairs to watch a movie. She tried to give me a hand job, but kept stopping because she thought her parents were going to catch us. At the end of the movie my girlfriend decided to take a shower before bed. She jumped in and the shower upstairs by her sisters bedroom and as I turned to go down stairs I noticed her sister was still awake in her bed. She smiled at me and I walked over to her and for no reason I kissed her on the forehead and said goodnight. As I pulled away I noticed she was smiling so big it caught me off guard. I paused for just a second and my heart started racing. I leaned back in and kissed her again on the forehead and then on her nose and then on her lips. I pulled away again expecting to see horror on her face, but she was smiling even bigger, so I kissed her again. This time parting her lips with my tongue and going for it. She responded by matching me. I stood up and looked at her in the near dark and pulled her covers back from her chest down to her waist. She had on a t-shirt and pajama pants. I was hard as a rock and she saw it. I put my hand down he shirt and cupped her left breast. It was huge and firm with hard nipples. I kissed her again and felt the other. She laid still not knowing what to do. I stood up again and ran my hand down her stomach to her waist and put my hand between her legs and touched her over her pajama pants. I went right for where her clit would be and she gasped. I rubbed her for about ten second and then went under her pants and underwear for her pussy. At the same time I took out my cock and put it in her hand and she started stroking me. I rubbed her soaking wet teen pussy for maybe 15 seconds and told her "put it in your mouth." She turned her heard toward me dick and it disappeared into her beautiful face. It felt so damn good. I put a finger inside her and she yelped. Holy shit, she's a virgin I thought. I had her get naked, which she was reluctant to do, but I rubbed her clit faster and she complied. She laid back down on the bed and went to put my dick back in her mouth, but I said "no, spread your legs I'm going to get on top." She spoke her first words "But my sister could be out any minute." And I told her she knew full well her sister took 20-30 minute showers and I climbed on her bed heart racing at the thought of deflowering the second daughter in this family. I was between her legs and I looked down at her body. Huge firm boobs with light pink nipples, wide hips with toned legs. Her pussy was bushy, but not overgrown. She was wet with her own juices so the hair looked matted in places. I spread her legs far apart and her pink pussy opened. I asked her "are you on birth control?" She nodded yes. And with the acknowledgment I put the tip of my penis up against the opening of her pussy and slowly pushed inside. She yelped again, but covered her mouth with her hand. She was so tight, so warm and so amazing feeling. I pushed halfway in and stopped, asked if she was OK and then continued until I was balls deep. She whispered in my ear "we can't make any noise my parents will wake up." I nodded and kept my pumping to a minimum, just moving my cock around in her amazingly tight pussy. I reached around behind her ass cheek and started fingering her asshole, which she noticed and asked what I was doing. I said "feeling your other hole" and then I put a finger inside using her pussy juices as lube. She started kissing me like a crazy person at this point, which was so hot. We are maybe 5 minutes into our encounter and I'm fingering her asshole, amazing. Her pussy is making my cock feel unreal. The taboo nature of this made it better than any sex with her sister. I fuck her for a few more minutes and am getting really close to climax. So I whisper in her ear "I want to cum inside you so when I leave part of me is still inside you." She whispers in my ear "I can't get pregnant. My family would kill me." I tell her "if you're on birth control you'll be ok. You're on it right?" And she nods yes again. So I say "Ok, you'll be ok. I'm going to fill your pussy with my sperm." She starts to kiss my neck and it sends me over the edge. I thrust as deep inside her as I can and I shoot stream after stream of cum deep inside her pussy. When I'm done I sit up on my knees still inside her and spread her legs far apart and start fingering her clit. Within 30 seconds she's cumming hard. I giver her nipples a little suck, kiss her passionately and then get off the bed. Get dressed, but before I go I spread her legs and lick her clit one more time. I notice liquid oozing out of her and then I go down stairs to bed. Her sister finishes her shower a few minutes latter not knowing what has just happened.
Over the years we have fucked multiple times. Each time amazing.
I married my girlfriend and her sister is now my SIL. It's a lot of fun daydreaming about taking her virginity, her doing her first anal with me and remembering all the times she swallowed my cum in the presence of of douche bag husband.