Encourage their silly behavior in social getherings.
This weekend I was at a dinner at somebody’s home and this 7 year old kid was driving everyone nuts with his “mature” jokes. He was talking like an adult and all his mama did was laugh like this -->:CareBear:.
No one was enjoying his jokes and we all tried to change the topic, then he started off with the kids. My daughter came up to me and whispered, “mom is that boy joking with us or is he serious?”
And all his mom did was laugh and say “oh my son is so funny.” 
She should have just taken him aside and asked him to hold off on his jokes until they were home 