My nephew and I spent the most of that evening dancing, and when ever we danced, I could feel his stiff penis against my leg, and I would turn to rub myself against his stiffness.
It was so erotic being able to do this with him while the rest of our family was standing around, totally unaware of what we were doing.
I was however, not prepared for what my nephew did next. It was suggested that the lights be turned down and when we again came together in a dance, he pulled down the zipper of his trousers and allowed his penis, covered in his underpants to protrude.
Somehow, under the cloak of darkness, he managed to lift my short skirt and his hard penis came into contact with my vagina, and he allowed his penis to slide along the length of my crease.
I nearly fainted, and right there, in front of all our family members, without them suspecting, I gave my nephew my first orgasm.