I was eleven and I shared a bedroom with my three sisters. I was the middle girl, my older sister was thirteen at the time. I was was in bed, just at the point where I was not quite asleep but not really awake. My older sister got in bed with me, though that wasn't unusual, since we'd been sharing the same bedroom forever. This time, Shari began caressing the inside of my thigh, going higher and higher until she was holding me, rubbing, her fingers tracing the along my nether lips. She's also had found my nipple and was pinching and caressing my breast. My body responded in growing intensity and these new feelings and sensations were overwhelming. As I came fully awake my sister began to kiss me on my mouth and her fingers had finally penetrated me, and expertly found just that spot that shortly brought me to my first real ******. She stayed and cuddled with me and we slept together that night.
In subsequent nights, she taught me how to reciprocate and we shared each others beds from then on, and together introduce our youngest sister to the Saphic joys. The three of us still enjoy a physical relationship from time to time, much to the enjoyment of our respective mates.