She is fresh home from college and her tits are huge! You buy her all new smaller shirts because since shes been home you have been plowed by step-daddy so much and you dont want him to stop. You get her to try on all these small tops and she suspects something when you talk to her about her huge boobs and getting her to pose for you and show off her off. She eventually figures it out that step-daddy is so turned on by her huge tits that you are getting fucked all the time. She finds it weird but she also finds it flattering and agrees to help you out.