Ups in relation

I was a late born to my parents. My sister age is 5 years more than me. Parents always take care of me. When I was in 7th standard i saw my mom making some sounds. Dad was on her and they both are involved in sex. At that I don’t know about it and I asked my mom about they did. She told it was a game that can be played between wife and husband. I remain silent. Few days after I heard same sounds and got excited to watch. I saw my mom in nude but, on her it was her brother. I got confused and asked my mom and she shocked and told that it can be played between man and woman. There are only two rooms in our house and i used to stay in my sister room. By the time I grown up to 19 she become full woman with excellent structure. I saw her in different angles even in naked too. She never ask me go out. Sometimes she asks me to adjust her dress like bras, blouses, and sarees. But I never touched her bare body. Sister sees my dick when it goes eruption. She teases my dick for that eruption. One day i noticed sister was watching porn videos and rubbing her body, pussy very hard. She kept silent when I came infront of her. On that night we both heard the voices of mom and uncle where dad went for trip with his friends. Mom voices disturbing us and I was getting horny. I know that sister too got horny and I asked her can we both make that sounds. She shocked and told it was wrong. And I was trying to convince as it was just a game between man and woman. If it is wrong why mom and uncle did it? She then convinced and agreed.
For the first time I got chance to have a lady and that too my sister. We both become naked and sister was playing with my dick and I was pressing her boobs very hard. She started making sounds and I was kissing on her lips. Without any late i placed my dick in her pussy where she made loud voice. I stopped her voice with my lips. We slept attached with each other in naked for that night. Early morning mom came to wakeup us but by seeing us in that position she was firing on us. I replied that you told me it was a game like you played with uncle. She shocked and told us it was wrong. But infront of mom once again we both made for one more time. Mom kept silence because I knows she has relation with uncle and she can’t able to threaten us.
I told to my uncle that I had sex with my sister and also about mom watched us. We both then got a cunning idea that to swap the ladies. Mom always prefer sex in dark without lights. When mom is ready for sex she kept naked on bed and uncle goes and fuck her. This time in place of uncle its my time to go. And with sister uncle will carry-on. Sister agrees to have sex with uncle. That night when uncle came to off the lights and to close the door i entered inside and uncle went outside. Now in moms vies i was uncle and she remain naked on bed. I undressed myself and started pressing her boobs and sucking them. When she was making little sounds i started to press them hard. I then placed my dick into her and she made bigger sounds than early days. As my dick was bigger than uncle and mom asking it was hurting but I closed her mouth with my mouth and fucking her deeply. I placed my dick into her ass where she begged me to remove. Then I placed my dick inside her mouth to cum and she swallows it. Again we both are having deep sex then I got too horny and I tied her both hands and legs with clothes and even inside mouth also. I then started beating her ass and pussy very hard. Pressing her boobs so hard and she was moaning high. Then I went to on the lights and mom shocked me to see there then in light i once again started having sex. She closed her eyes and accepting me to do. After removing her clothes she roughly threatens me where I hardly forced her on bed and placed my dick. We both went to my sister room where uncle was fucking sister. From then onwards we four started to have continuous sex. I was very lucky to have mom and sister in younger age.
It was very proud for any boy as his mother was her sex partner and sister was my sex god to me. Later i came upto know that I was son born to mom and uncle and not to dad. Uncle reveals mom affairs with him and some others before marriage. After marriage her dad also fucked my mom. It was very crazy to hear these things.