I am a white male aged 25. Middle class.
I’ll keep it brief: from about age 10 to about age 16, I had sex with my brother, who is four years younger than me. The sex was almost always oral sex and rarely ended in orgasm, although I do have fond memories of ejaculating in his mouth and on his face, as well as swallowing his sperm. Mostly, we did 69.
It started when he caught me fooling around with neighborhood boys and wanted to try it. There was a period of about two years where we did nothing at all; then we started up again when we both started sneaking downstairs late at night to watch our father’s (heterosexual) porn videos. We would get very horny and masturbate openly, then have oral sex. My favorite memory is when we had a hot three way with a mutual friend who was a year younger than me. He was spending the night at our house; the three of us played strip poker and then shared oral sex and orgasms for hours.
It only happened once but I will never forget it.
I do not think it affected me adversely; I fantasize about it now and would love for something similar to happen even though I consider myself mostly heterosexual and have a great sex life with my wife-to-be. My brother and I are good friends nowadays and enjoy spending time together, though we make no mention of our sexual past and I dare not bring it up. This past incest experience leads me to wonder if I will be sexually attracted to my own children; that is the only part that concerns me now.