I'm a 45 year old mom now but when our parents were in a commercial airline crash in 2001 my older brother and I had no one. I moved home to live free and so did he. We were basket cases for close to 6 months! We were drinking vodka straight up one evening and as is said: "One thing led to another." Over about 3 hours we dared each other to undress and show what we were always curious about. From somehow giving him a b******* to eventually having full on sexual intercourse, I felt completely comfortable and enjoyed everything. The next day we just said, "What the h***. It was something to do" and it was our secret. Over almost 7 months we did it 19 times (always rationalizing it with vodka) and then we just stopped. When we started seeing a shrink for the loss of our parents we both opened up to him. We talked it out and neither of us has a hang up about it. We're both married with kids but have never had the desire to do it again. Do not do it! One of you will not have the mental and emotional strength to just see it for what it was (two people f-cking) and someone WILL get hurt and ruin a beautiful sibling relationship!