Helping stepmom stretching ass to my daddy

I saw that my stepmother was wearing an anal plug, so I decided to prank on her. I stuck her butt plug on the couch and woke her up. She got mad. I asked her why she was wearing an anal plug and she said it was her wedding anniversary and she was stretching her ass for my daddy. I told her to show me the progress and as I saw that the ass hole was closing I decided to help her.