Definitely have to tiptoe like crazy if you want to have anything resembling a conversation that adults might have. Any jokes or banter that could be construed as PG13 or higher should only be heard by friends you trust.

I learned early on how strict this game is when my forum account got suspended after I made a facetious comment about using shirk to kill healers in DF. The suspension came with a warning that forum infractions could cause me to lose access to my SE account permanently. That's more money and time invested than I'm willing to throw away, so most of my conversing in-game involves family friendly macros, and I make sure I play nice on the forums even when arguing with people.