My sister was on the swim team in Jr. College. She looked so hot in her bathing suit. She is 19, 5'5 125 lbs. with green eyes and dirty blond hair. She had big boobs too. She was a double d cup. I am 18 6'3 150lbs brown hair green eyes. She would always walk around the house before her practice and meets in her bathing suit. Every time I saw her in her bathing suit I would get hard. I would always try to sneak pictures of her when she would lay out in the back yard tanning.
She would leave her bathing suits in our bathroom to dry. After every meet or practice I would sneak in and stroke myself and cum in the crotch of her bathing suit. She had no clue I was doing this. One day she took her suit off and put it in the bathroom. I sneak in and came in the crotch. Right after that she went back in and put it on again to go lay out. It was still damp from the pool so she did not notice the crotch being wet. I went to my room and jacked off knowing my cum was rubbing on her pussy.
Our dirty close hamper was in the bathroom as well. She would leave her bras in there and I would cum in them as well. By the time she picked them up they were dry. One day she left her bra in the bathroom by accident and I came inside of it. When I left and went to my room I saw her go in the bathroom after me. When I went for dinner, my sister was wearing a tank top and I could see the color of her bra. It was the one I came into. I wondered if she knew. She never once even gave a hint that she knew.
The next day when I woke up I went into the bathroom. I had my normal morning wood. When I walked in, I noticed a bra on top of the hamper. I was still half asleep and did not think anything of it. I knew my sister had taken a shower But I know she dose not sleep in a bra. I always saw her hard nipples poking out from her night shirt. So I relived my morning wood into both bra cups. Then put it back. I then left and went back to my room for a bit to wake up before my shower. When I went back into the bathroom to take my shower the bra was gone. I took my shower and went to school.
When I came home from school, I had to pee. I went to the bathroom and peed. After I was done, I notice my sister's panties laying on the floor. They were white with smiley faces on them. I have never done anything to her panties before but I said why not I needed to get off. I unloaded all my cum on the crotch of her panties and put them back. I went into my room for a bit. I got thirsty. So I went down stairs to get a drink from the kitchen. When I came out of the kitchen and back though the living room. My sister was sitting in the chair that faced the kitchen. She was wearing a tank top with the bra I came on in the morning and short skirt. When I entered the room, my sister spread her legs open and I could see up her skirt. When I looked, I noticed that it was the same panties I just came in a few minutes ago and you can see the wet spot from me cumming on her panties. She started to rub her crotch and press the cum soaked part of her panties into her cunt. I knew I was busted but she did not say anything and just closed her legs as I went back up stairs.