Your girlfriend just left to run errands and her big tit step-mom comes in and notices you alone. She takes this chance to see if the two of you are sexual active and when you say no she takes this as a learning opportunity. She asks you to take out your cock and tells you to grip it, while trying to make you harder and harder. Eventually, she is so pleased with what a good boy you are she let's you cum all over her massive tits before, your girlfriend pulls in the drive way and you're told to go get cleaned up.