This is a scene that I actually edited out of one of my novels. I came across it as I was sorting through files and thought I'd see what you thought. You might recognize the names, Kara and Jacob, if you've read my work before. It's a quick sex scene between two lovers separated by anger.
Jeremy is a nursing student and his roommate's mother, the 40 year old Jaime, a beautiful woman who one night asks Jeremy for some professional help - to show her how to do a breast exam. By the next morning their relationship is anything but professional.
Josh, while taking a break from his stocks and securities activities, encountered a troubled woman in Hawaii. He wound up in the middle of a debacle, between a sibling rivalry and an Adonis, but wound up making the trade of his life. The sisters/lesbian tag comes to light very, very late in the story and is not a prominent theme.