Beth "Jealous Stepbrother"

Your parents have gone away and left you and your stepsister Beth in the house alone for a few days, Beth bought her boyfriend back last night and you heard them having sex. You threaten to tell your parents and Beth realizes you are jealous that she is getting all of the action, she decides to make you a deal. She will let you have a wank over her while she fucks herself with her toy if you agree not to tell anyone that she had her boyfriend over.