19 Years ago.
Over the years. I witnessed a few things in my backyard that were very exciting. We had a built in swimming pool and hot tub in the backyard which had a lot of trees around it so our neighbors couldn't see our property. After my first encounter seeing my sister get off I became addicted to watching.
Over the course of the summer I watched my mom and sister get off multiple times in the backyard. I jerked off as many times watching them and they had no clue. Being I was jerking to them all the time I did something daring one day. My father was out of town on business and my mom and sister were out back tanning I started jerking off but didn't let myself cum. I saw them walking back in the house. I was in shorts and no shirt so when they started walking up the back path I went into the bathroom and left the door open. We had a bathroom right near the backdoor of the deck so when you walk in you can see directly into the bathroom when you look to your right. I hear the door slide as my orgasm ripped through me I didn't even care I was cumming so hard. It seemed like it lasted forever. I was like Uh Uh Ah I'm cumming. As I looked over my mother and sister were staring directly at me with their jaws wide open. I looked at them they looked at me and they walked away so fast. I heard low whispering and my sister laughing as they walked into the kitchen. I cleaned up the cum I shot all over the toilet seat. I was so horny I didn't think of the consequences that I would have to face my family about what they had just seen.
I was going to go to my room but I had to walk past them so I had my shorts on and put on my shirt. I walked through the kitchen and my sister started laughing and I looked at my mom and she had this little grin on her face. A couple hours past and I got a knock on my door from my mom and said we have to talk. She said I guess you know how to take care of yourself now. It's no big deal we were just surprised what we saw and were in shock. Lock the door next time. It is something you should do in privacy. The next day my sister was brutal to me everytime she walked by me she would make the jerk off gesture to me and I wouldn't say a word. That night we were fighting over the tv and my sister goes to my mom hey mom who am I and she starts making the jerk off motion. I thought my mother would defend me but my sister was making a funny face and my mom started laughing. I got so pissed off I am like what are you two laughing at? Every chance you get you are both fingering yourselves in the hot tub like it's your job. I looked at their faces they look stunned and I stormed off towards my room. I could hear them whispering as I was walking away. No sooner than I shut my door my mother and sister were both at my door saying what are you talking about? I said I dont want to talk about it leave me alone! My sister said what did you see in a stern voice. I said I saw everything. I saw the both of you rub yourselves in the hot tub until you started shaking and moaning. They looked so embarrassed. I said now you know how I feel after you two saw me. My mom said it was wrong for me to spy on them and that they were sorry for seeing me. I accepted but I realized I ruined a great thing I would no longer be able to watch them.
Months went by and my sister had a question for me. She said promise you wont tell mom. Remember that day when we caught you? Yea? Do you usually shoot that much when you cum? What? She repeated the question. I said yea most of the time. She got real quiet and didn't say anything. I said why do you want to know? She said because it was a lot. What does it feel like for you? I said it feels like strong contractions every shot feels amazing. I asked her the same and she said it feels like rolling waves and her stomach and pussy contract strongly and it feels like an explosion. I was getting horny and she said I would like to see that again sometime. I said you want to watch me beat off. I am 13 years old my sister is now 15 and she wants me to jerk off. I said only if you do it first. We went into my parents master bathroom and she sat on the toilet and I was standing. I started stroking she started rubbing and she went and got hair conditioner and squirted it on my dick it was so slick and I never used anything before for lubrication. My sister said can I try and started stroking my dick which felt so great. 30 seconds I told her I am gonna and I started shooting my cum all over the place. I dont know what got into my sister but she wouldn't stop stroking me and I was so sensitive so I sat on the toilet and was squirming. She said I want to get every last drop out of it. I was making noises I never made before. I was whimpering almost crying. She finally stopped after me begging.
I didn't think about it until days later but my sister never let me watch her finish so one day when my parents went out I told her it wasn't fair. She agreed but said if I do this for you you have to promise not to jerk off for four days. I was psyched and said Yea! She went at it hard and fast on the couch pounding her fingers in and out and rubbing her pussy she let out a few oh fucks and moans and shakes. I was hard and went to bed that night with achy balls.
Four days later I was climbing the walls I couldn't wait for my parents to go out with their friends to dinner. As soon as they left she said are you ready? I said yea. Get undressed and go lay on your bed and she came back with two bandanas and said do what I say or I won't stroke you. She told me to put my hands back and she tied them up. She came back with hair conditioner again squirted it on her hand and began cranking my dick. I never felt anything greater in my life up to this point as I started cumming ropes my balls were so tight and my dick was pulsating. One shot I saw before I closed my eyes shot up like three feet but I had no clue where it went. My orgasm was finally over but my sister had other ideas she kept going like last time and was ruthless about it calling me a pervert and a pig and she started to squeeze the head of my dick hard and twist as she went up. She was taking her finger nails and was running it along the head of my dick. I was whimpering again begging her to stop. It was probably only two minutes but it felt like forever as she was torturing my dick. She cranked on it as I had tears of pain and pleasure coming down my face. She finally stopped, untied me and I looked at her chest and my stomach, my cum was everywhere. It was one of the best feelings ever.
It never happened again until 15 years later. That story I will have to tell at another time.