A story in the The High-school Affair Universe
After Karruche manages to get out of the house unnoticed, Jay thinks he is in for a quiet weekend but his sister Kara has other plans. She makes a move on Jay, and unbeknownst to the 14 year old boy, another family member wants him for herself and will resort to blackmail to get it
An adult brother and sister (with flashbacks to their teen years) and his two teen daughters and their life together, swinging with neighbors, until they come to realize that they are more than just brother and sister. Note there is bisexual male/male sex and some watersports.
A boy grows up with the forbidden love of his little sister and discovers he loves to be nude. Knowing he can never have his sister, he joins the Navy and is away from home for 20 years. When he retires, he rescues her from a bad marriage and has her move in with him. That is where they finally admit their love for each other.