"It was probably my biggest regret for most of my life after that and I feared that he had deep seated resentment for me. He's pretty much the only family I had left, and I was afraid that I would lose him too due to my selfishness.
"It took over 10 years for me to finally go to him and ask for forgiveness, and to my surprise, he wasn't mad at all. It was a huge relief, and he and I aren't awkward around each other anymore."
Another man claimed he had sex with his sister when he was 17, and she was 14. Following the encounter, he immediately felt ashamed.
"I ran to my bedroom and covered myself under the blankets with a huge shame feeling. I spend the whole night wondering if I raped her or if she actually wanted it.
"The next day she acted normal, but I couldn't look her in the eyes.
"I felt shame for years, even though I really got the feeling she also wanted it, the guilt was so much.
"That happened over 10 years ago. We never talked about it. It's a closed deal for me, I had to live with a huge guilt and shame, and I was so confused that night and the following days."
Other Reddit users shared their encounters with close cousins, and some were incredibly relaxed about it.
"I can't say I disliked it or I feel guilty or anything. It is amazing, she's hot and thinks I'm hot as well."
Another echoed his sentiment: "I had sex with my cousin when we were both 17. It was consensual, and there were never any guilty feelings from either side. We only had sex the one time but I think it was because we both fell into long term relationships shortly after we slept together.
"Our relationship never changed after we slept together, this was over 20yrs ago, and we still talk on a pretty regular basis with no weirdness."
Astoninishly, one woman claimed that she and a sibling were still together.
"My brother and I engage in it every day. We've been together for 6 years and have two kids. It started because I was horny and just wanted to get laid. Turned into a relationship.
"My life changed a lot because of it. All the plans I had for after high school got thrown out the window, but it was worth it."