I would forget about the about the rude language. Instead I�d teach homophones, which will give them more than enough problems.  The odd rude words will come in automatically, but as it �s not explicit, you�ll get past it with some good laughs. I also have some videoclips from Espresso English, including one with the title: Bad English can be dangerous, which uses the difference between soup and soap, beer and bear, sheet and shit. As the last one is �embedded � in a normal lesson, we have a laugh, and move on.  (https://www.youtube.com/playlist?list=PLZYDF7k52kJeAPaxfDWdzln2Cb_Pg4fjz).  Cheers, Peter