I head into the bathroom with my step-son to help him change during a family party, we have no other room to use. I notice my step-son getting shy around me while I'm also changing in front of h8im. I reassure him there is nothing to be shy about. I pull his boxers down to help him change and his MASSIVE cock hits me in the face. I can't believe he has a bigger cock than his step-father. I decide that I have to suck his cock to help him cum so the family doesn't see his hard cock through his pants, after a while the blow job isn't working and I become so addicted to my step-sons massive cock and comparing it to his step-fathers small cock. Then I sneak into his room later that night and have to fuck him again, I'm so obsessed with his huge cock I cant help it, then the family catches us fucking and I don't even care, I let them watch as I fuck his huge cock.