He'll pause a scene, maintain eye contact and clap his hands together and - as a possible bonus - shout, "My man!" in the process. You kind of have to wonder if hands hurt from doing it that much, especially considering that he probably has to do a few takes or what have you. You ever go to a wedding and have to clap at the end of each speech? Eventually, that's going to hurt.
Here now, Denzel Washington clapping 200 odd times. Enjoy.