Played straight, then lampshaded into Cluster F-Bomb territory in Louis-José Houde's special Suivre la parade during an extended bit about his ex-girlfriend's abortion. He describes going home after the procedure and (after wishing his own father a happy birthday) listening to a new voicemail message from his agent: he's just won an award from a kids' TV station for "the performer that you'd would most like as a dad."
Houde:(after a long pause, quietly) ...Tabarnac. (audience laughs) I'm sorry, there's one swear word in the show, there it is — tabarnac. It's a tabarnac case, I have to, I'm sorry. At that moment in your life, I swear, that's what comes out — tabarnac. Tabarnac, tabarnac, tabarnac.
Context for English speakers: Tabarnac is a very offensive swear word in Quebec French.
Bill Cosby: So I asked, 'what is it about cocaine that makes it so wonderful?" He said 'Well, it intensifies your personality.' I said, 'Yes, but what if you're an asshole?'"
It's secondhand, but: Eddie Murphy did a hilarious bit about Cosby chiding him for his use of foul language. It culminates with Murphy-imitating-Cosby saying "Yooooooooooou (beat) cannot say (beat) FUCK. (beat) In front of people." In the mid-1980s, the mere suggestion that Bill Cosby actually said "fuck" is enough to bring the house down.
Poetry-reading rather than stand-up, but Taylor Mali lampshades this brilliantly with his poem, I Could Be a Poet:
"I am not afraid to use the one requisite swear word that lets you know I am fuckin' serious, man."
"Now, this doesn't happen to me very often, but about three weeks ago, I met a girl and she was real nice and she invited me to her apartment. So I went over there, and she had the best pussy I have ever seen —" [Audience laughter, cheers and catcalls] "Oh, now come on! I'm talkin' about her cat! Now that makes me sick, right there! No! No, you can't say anything anymore that people don't take it dirty, and I'm sorry, that disgusts me!" [Pause] "That cat was the best fuck I ever had, too."
Not sure if this qualifies as "stand up" but as there is no category for Sketch Comedy Record Albums... Monty Python's The Album of the Soundtrack of the Trailer of the Film of Monty Python and the Holy Grail has this in its "Introduction To The Executive Album Edition":
"Everything on this record has been designed to meet the exacting standards which you have naturally come to expect....There is little or no offensive material, apart from four cunts, one clitoris, and a foreskin. And, as they only occur in this opening introduction, you're past them now."
