Your girlfriend broke up with you and now there's nothing to do on Friday night. Your stepsister with small perky tits wants to know what happened and she thinks it's because of you couldnt fuck her well enough. So lets inspect how big that dick is. Is it ok for you to show your cock to her? I guess no harm no foul there. Only soon she wants to do more than look at it. That's the beginning of all the fun!