My basic idea goes like this: Hollywood is full of gold digging sluts who might try to get knocked up by sons of rich celebrities to get their money or try to become famous by having affairs with them and making them public.
To avoid this and to protect their sons, these celebrity MILFs form a swap club where they fuck each others sons, so the sons don't have to seek sex elsewhere. After all, why would a son fuck a random slut when he could fuck Halley Berry, Heidi Klum, Britney Spears or Angelina Jolie instead?
May or may not include taking the sons virginities. Might get expanded to dads/daughters. Possibly incest. Real ages may be adjusted to match the couplings.