The FCC has issued a lot of NALs and fines to Infinity over the past 10 years because of Stern. This isn’t the first time its happened, and Stern wasn’t able to talk about blow jobs 3 years ago (or 10 years ago, for that matter…I’m looking at an NAL from 1994, when there was a whole other set of Commissioners, proposing a fine against Infinity because Stern talked about masturbation and oral sex.
Check out Action for Children’s Televison v. FCC (1988). It said that the FCC has the authority to restrict the broadcast of indecent material at times when there’s a reasonable risk that children might be in the audience, which has been defined as between 6 am and 10 pm. If Stern’s show aired before or after this, the FCC wouldn’t have any grounds to take action against him on indecency.