When my sister and I were younger, I won't say an age but it was barely double digits. We would play outside then would wait until our parents were napping, go inside and shut our bedroom door by laying against it with a pillow. We never kissed but would go down on each other. We would grind our p***ies, scissoring if you will, before I even knew that was a "thing". I didn't get off until one night we were playing with each other under the blankets in bed and I jerked! We both went in the bathroom and I was like what was that! We continued for about a year then stopped. We never talk about now, 20 years later.