You've always known your Stepmom was a tramp, but you never expected to walk in on her fucking the cable guy. She spots you watching her get pounded from behind through a crack in the door. You can tell she kind of enjoys being caught in the act. Once they finish, she closes the door... you go to your room and wait for her there. You know she's going to come talk to you.
When she arrives, her tits are practically falling out of her nightgown, and her hair is messy from the sex she'd been having earlier. She looks smug and informs you that your dad is always off on business trips, and she gets lonely. You know she's trying to talk her way out of trouble, so you give her a choice. Either she gives you what the cable guy was receiving, or you will tell your dad.
Without much choice, she decides to give you exactly what you want.