Your birthday is coming up soon… you’re turning eighteen. You know what that means… you’re officially an adult, a new adult in the household… new age, new responsibilities… new privileges. I hope you’re as excited as I am… gee, so many new possibilities – opportunities – for you. I just want you to know… that, as an adult, now that you’re eighteen, you can fuck me any time you want. Yes, you can fuck your mother now… it’s perfectly natural… even if daddy’s in the room. In this house, fucking your mother is as natural as… saying “hello!” ANY TIME YOU WANT. Okay?

I’m a woman of my word… AND I take my role of motherhood very seriously. Honey, it’s just as I said when you turned 18: in this house, fucking your step-mother is as natural as saying “hello!” You just let me know when the urge strikes you… even if I’m barely awake and still in the bed in the morning, even if your father’s right here in the room. But… I’ve never… a blowjob?! Well, I… I never have with your father and… I never will. But, since you’ve asked… just because I’ve never granted that wish of your step-father’s, well, that doesn’t mean you’re going to have to go without. Just be patient with your step-mother… this is my first time. And, honey, of course I’ve never heard of a 69! But for you…

(Write a 5000 word spry base on this prompt. Include dialogue. It takes a two weeks before the son takes up the offer since he doesn’t initially believe it. He approaches his mum while her and dad are in bed ask takes up the offer).