I've given this one to people with complaints of buttinskis making bad matters worse by adding commentary where they shouldn't be.
Get a black figure candle of the appropriate sex for the offending party.
While carving an "x" over the figure's mouth incant:
"You did scream and you did shout
and put yourself in where you should have been out.
Now, in that place, I do shut your mouth."
While lighting the candle incant:
"So with your mouth shut, I bring myself peace
and now you are silent, so peace I can keep."
Let the candle burn out completely.