I lay back in my bed, staring blankly up at the ceiling. My naked, too-hot-to-be-true, older sister Amy snoozed innocently next to me. Her blonde hair splayed across the pillow in golden rivulets. Oh my God. Everything that had happened. It was almost too much for my 19-year-old brain to process.

My parents had gone to a work party the night before, leaving me home alone with my three sexy sisters: Amy and the twins, Jenna and Brianna. At age twenty-six, Amy was seven years older than me, eight years older than our younger sisters, and light years away from wanting to spend time with her less mature siblings. But...