I'm not sure if every child goes through this so I won't make a blanket statement. Some kids go through a phase when they learn words like "snot" or "booty" or "poop" that saying it makes them giggle and they and their friends often use this dirty talk in all sorts of conversation pieces.
My son (almost seven years old) has been in this phase for a year or so now and while his peers have moved on and are finally wanting to converse about other things, he often replies with some form of this dirty talk. From what I can tell among his peers, it's getting kind of old. Also for the adults in his life, to include us (his parents), his friends parents, and his teachers, we're getting kind of exhausted of hearing every other thing being "poopy" or "snotty".
I've tried the talk encouraging him to move on. We've encouraged him to talk about other things with his friends and while sometimes he does it always seems to revert back. When he mentions it at the dinner table, it gets a stop put to it immediately. We also don't participate in it nor do we laugh.
How can we encourage him to move past this once and for all?