Surprise Sleepover

A friend and I when we were both about 12 or 13 would sleep over at the other's house almost every weekend. The high point of the sleepovers was always our mutual masturbation which we had been into at least since we were 7 or 8. Usually we waited until his parents and siblings were asleep before getting at it. This saturday night we had had our mutual JO, and had fallen into a deep sleep. About three o'clock in the morning I awoke when I heard loud talking comming from his sister's room. My friend was awake as well. When he saw that I was awake, he gestured for me to keep quiet whispering that his 17 year old sister had overstayed her time limit, and was sure to be spanked by his mother. Just after he said this, the first blow fell on her behind with a loud crack, so she must have been being spanked with a belt or strap. The swats came fast and hard, her cries became more desperate, and finally were a continuous sobbing. Both of us got raging hard ons, and began jacking off to the rhythm of the licks landing on his sister's hind end. The spanking ended after about two or three minutes after we had begun jacking, so it was a few minutes later that we came. When things quieted down, I asked him if it wasn't unusual for a 17 year old to be spanked. He said that she has a time limit of 1 o'clock to be home, and had been warned after several violations that the next time she was late getting home from a date, she would get a spanking. He claimed that he could hear his mother tell his sister to take off her her panties and give them to her. Then after his mother smelled them, she had his sister remove the rest of her clothes and the spanking began. By the time his explanation ended we were both hard again and got in another JO. I was fascinated by the thought of a girl that old being spanked, and the fantasy inspired my jacking for the next several weeks.