I was 22, my sister was 20. Almost 21. We both were still staying at home. I was looking for a job, she was in photography school. Now we got along for a brother and sister. My sister is very pretty but I never had never and would never thought of or have sex with my sister. Even though I have masturbated thinking of her catching me masturbating. I wasn't lucky with females and she was the only one that I really knew and was close to.
Anyway, this one day we were at home folding clothes and we were talking and she brought up maybe someday I can take nude photos of you. I was taken aback at first wondering if she was serious. So to see if she was serious I said ok. She looked up at me and was like what are you serious? I asked if she was serious? We had an awkward silence then both said at the same time yes. Which I was kind of half serious and half not and found out later so was she. I felt a stirring down below but nothing major. So we picked a Saturday that we knew that mom would be out shopping. When mom goes shopping she is gone all day.
So, the day arrived and once we were alone my sister said that I didn't have to do this if I didn't want to. I said its ok I don't mind. She made sure it was warm enough for me. Once she got set up she said anytime I was ready I could take off my clothes. So I started taking them off and set them aside. Once I was fully naked I was facing her. I saw her eyes go down to my penis and it grew just a little bit but not much. I was able to control it not getting any bigger at the moment. But I did see a smile come over her face though which I almost lost the control off keeping myself soft. So we started. She took her pictures. I posed. About an hour or so later she said lets take a break and if I didn't mind I could just stay naked. I said I was going to.