no i haven't fantasized about my sister but i have of a distant cousin. we weren't direct cousins but somewhere along the lines
i am the right half of a siamese[conjoined] twin....but....i am left handed...my brother is right handed....so we wack each other off all the time...we only have 1 dick too so we gotta share....some times we also do a reach around on each other but only when we have been drinking
I used to share a bedroom with my sister for many years. She was 3 years older and I haven't fantasized anything about her.When my cousin taught me how to masturbate I didn't want to wank just in the bathroom but in my bed as well. So every night I was expecting her to fell asleep in order to jack off. One night I was jacking off and she suddenly told me that she knows what I was doing, that it was perfectly normal and that she was also doing it every single night. Since the we were very open to each other and we masturbated together almost every night till the moment she left for college.
As my brother & I shared a room nudity was never a secret - plus my family were also inclined towards naturism anyway. Being some years older than my brother I was into masturbation long before he hit puberty, although he would still enjoy watching me. On many occasions he would try copying me, but with no success - he just complained that it just burned. Then one day it happened. He had his first orgasm, along with a small amount of semen, and he had entered into manhood. I remember that the excitement of witnessing this birth into a new stage of sexual experience aroused me so much that I also climaxed there & then with hardly any further stimulation required. We occasionally enjoyed joint sessions after that, but most of the time we would masturbate individually - although there was never any embarassment between us. If either of us walked in on the other we would just let them get on with it, and maybe even start a session of our own. It was just an everyday thing.
probably their mom's. give the kids some fucking legos and get them out of her hair for a bit. "honey, stop masturbating with your brother! the car is all packed up and we need to take you to college now!"
So did masturbate in front of each other so that you could see each other's genitals? I would think that would have caused you to start associating your sexual arousal with each other.