Made My Younger Sis My Personal Whore

So long ago when I was 15 I lived with my parents and my younger sister. My sister was 3 years younger than me and my parents always wanted to look after her while they were at work or out with their friends or whatever that had them out of the house.
We had an allowance for chores we do and my parents got me to keep from complaining about watching my sister by increasing my allowance for it.
My parents were out of the house so much that we didn't really spend time with any other kids except when at school and this was a big problem for me because I was a teenage boy that was horny all the time.
Where we lived there weren't any neighbors or anything close enough to walk to so we stayed home when the school bus dropped us off.
One day my parents were going out with some friends after work and they usually got home late which meant me and my sister wouldn't have to worry about following our bedtime. It was a good thing for me because a really hot girl at school wore a dress and I was able to see down her dress even though she was wearing a bra and I got a glimpse at her panties when I bent down to pick up my pencil, all this meant I was even hornier and was gonna spend a lot of time masturbating.
I had jerked off a lot since we had got home when I suddenly had a very risky idea. I'm wasn't blind and was practically raising my sister so id seen her in her underwear and even naked at times and I enjoyed it and thought she looked good especially her butt. My idea was to use my allowance to convince my sister to let me look at her while I jerked off and cum on her.
I went to my sister's room and told her how I'm horny all the time and can't get a girlfriend because we live far from everything and I have to take care of her and I want to look at her naked while I jerked off and cum on her and she can't tell anyone.
She kinda freaked out at first but calmed down a little when I pointed out that I already see her naked sometimes but she still kept refusing. I wanted to see if I could convince her just by asking but when she refused I knew I definitely needed to use the my allowance.
I reminded her that she always spends her allowance so fast and complains that is because she gets so much less than me and I told her that id give her half my allowance if she did whatever I wanted whenever I wanted to help me cum. She actually thought about it for a few minutes before agreeing.
I gave her what of my allowance I still had left at time and had her undress and lay down with her legs spread while I jerked off and came on her stomach.
After that first time I used her a lot and had her pose in different positions, my favorite being on her knees legs spread with her face down. It gave me a great view of her ass and bare pussy and I made it possible to cum on her ass and her pussy.
She never complained or told anyone. She just collected her money from me and did what I wanted. Eventually I added touching her, then her touching me and then jumping her. When I say humping her I mean I just hump my dick against her pussy or ass and sometimes face.
One day when I had her face down on her knees I was humping her ass and just decided I had to fuck her pussy so I just went ahead forced my dick into her pussy. It was kinda difficult because she was so tight but it helped that she did get turned on by what I would make her do so it meant I was going in dry. That day we became each other's first.
I continued to pay her to use her body for a few more years and continued for two more years without me having to pay her.
She ended it when she had a pregnancy scare.
My younger sister is so hot which makes me think of all those times years ago and I think of trying to get that started again.