You’re going to have to provide more information. What did he say instead of xxx? Presumably, it is a word that is also the name of a famous dog that would be familiar to people in your locality but not to you. I don’t know too many famous dogs — perhaps Lassie (fictional) or Snoopy (cartoon). As far as your colleagues’ whispering that you probably wouldn’t get the reference — they were right, weren’t they? Perhaps they were afraid you might be offended if they explained it to you. If you wanted to know, you could have just asked them about it. You still could ask them — I’m sure they’d be happy to see how interested you are in the local culture.? Honestly, though, I wouldn’t even give it a second thought.

I dont understand the question. Did he actually say "xxx"?

Don't be afraid to ask if you don't understand!