"So how many people here have actually taught their young children (if and when they were young) to use the kind of expletives they have on here?"

That might be a good way to get them to clean up their language.

"Now children, I've written the words on the board with little stars in place of some of the letters, and I want you to fill them in, and write down sentences making use of them."   

"No Johnny f**K does not mean "fork" - you can't have been paying attention. I'm going to have to ask you to write the correct word out one hundred times before you go to play...""