For the third night of Chanukah, I took Maxon to see one of his favorite comedians, John Mulaney. I would say that Mulaney is rated PG-13 for mild language and mature situations. But the comedian who opened for him, Seaton Smith, was definitely rated R.
Now, just like I don't expect to see Sin City: A Dame to Kill For and Dracula Untold movie trailers before Guardians of the Galaxy (I'd like to have a word with you, Walt Disney Studios), I don't expect the opener for a PG-13 comedian to tell jokes about tuchus schtupping.