Brother and sister2

I have been having sex with my sister know for over 2 years. She has a boy friend know and she does not come over as much. I changed shifts at work and know work Monday to Thursdays. When home by myself i still go around the house naked. Every Friday morning i go down the back yard and spy on the couple behind. They have breakfast on the back patio and most of the time naked. I have watched his wife suck his cock and him eat her pussy. Most mornings he fucks her. She started telling her husband she was having a girlfriend coming over about 9.00am. The 1st time she did i came down the backyard and watched them. She only had a towel on and her friend was dressed. I watched them for a while and she dropped her towel and her friend stayed dressed. I then heard her ask her friend if she wanted to join her naked. When her friend stood up she went and joined her and helped her get undressed. This was the 1st time i had seen 2 women and naked. It was not long and i cum. I stayed and kept watching. After they were both naked they cuddled each other.
Then they kissed each other. As they kissed they both started fingering each other. I watched as they put fingers into each other. It was not long and they both cum. They went inside and as they did she looked back and smiled in my direction. I think she knew i was there.
I walked up towards the back of the house thinking about what i had seen. I was horny so i walked down the side of the house to the side fence, hoping someone would see me naked as they walked pass. I was watching and out of the corner of my eye i saw a lady standing in the bushed looking at me. I said hello and she answered back. We talked for a while and she kept looking at my cock. I asked if she would like to come inside and join me. She said not to day but maybe another day. I told her just to knock on the front door when she wanted co join me. I asked her name and she said Ann, she then left.
It was two week until she came back and she knocked on the front door. I opened the door - naked - and invited her in. She had a dress on and sneakers. I asked her if she would like to join me and she said some other time. We chatted for a while and made a cup of coffee. We sat on the lounge opposite each other an i noticed her looking at my cock. It turned me on. I noticed she opened her legs a bit and i could see her undies a bit. I asked her how old she was and she shocked me. She told me she was 42 and she asked me how old i was. I told her i was 22. She then asked me why i go naked around the house all the time and i then told her i love being naked. It was not long and she said she had to go so i let her out and told her she was welcome any Friday and she left.
It was another 2 weeks and she came back. I asked her if she wanted to join me and she said maybe a bit later. She then asked me why i go down the back yard so i told her. I then told her if she would like to see i would take her down there, but she had to be hear by 6.45am. We had a cup of coffee and i cleaned up. I went to the bathroom and when i come back she was standing at the back door. I walked up behind her and chatted for a bit. i worked up the nerve and unzipped the back of her dress. She held the front of the dress up and i pulled the back down and she let it go. It fell to the ground and all she had on was her bra and her undies. We spent the next hour with me naked and her in her undies. Before she went home i took her outside and spent about 15min before she left.
She came back the next Friday a bit early than i told her. I let her in and asked if she wanted to join me. She looked at me and dropped her dress, only had on was her bra and her undies. I took her hand and led her to the back yard and showed her where to stand so we could watch. It was not long and they came out - both naked. They had there breakfast and then started to kiss and play with each other. She dropped to her knees and started sucking his cock. Ann was just staring at them. I was rubbing my hand up and down on her back. I took a chance and unhooked her bra and let it drop to the ground. Ann tried to catch it but did not catch it. I reached around and cupped her tits. Her nipples were big and ling. She did not stop me. Playing with her nipples i sensed it was turning her on. I then slipped both my hands down to her undies and slipped them off. she just stood there and watched the neighbors as they were fucking. I was so horny so i fingered Ann and she just let me. It was not long and the neighbors went inside. I picked up her undies and bra and started to walk up to the house. Ann took my hand and led me to the side of the house and the side fence.
We faced each other and started to kiss. We kissed for a long time and all of a sudden i felt her hand on my cock jerking it. I sat her on the table and she opened her legs wide and fed my cock into her pussy. She was wet and it slipped all the way in. I told her i wish someone would watch us. Nobody did but Ann said there had been 4 people walk past. After we finished we went inside, cleaned up and she left. Before she left she told me she would be back next Friday.