Smoking Mouth Special Effect?

For a short film I intend on doing later this year, I wanted to add some type of special effect for a speed talking/rapping shot, and I wanted to see if there was a way to make it seem like their mouth was smoking from talking so fast (NOT CGI). In the shot, the actor will be holding a microphone, and I was wondering if there were any tricks I could use that could maybe use the microphone to emit smoke for just a short while.