What does "Pow, right in the kisser" mean?

The phrase is slang for hitting someone in the mouth. However, I'm sure Family Guy was referring to when they used it. Peter's brother-in-law(not his cousin :] ) despised the phrase because it had to do with his mother's ual affairs and how he walked in on his mother during one of them. The man having with the mother said "Pow, right in the kisser!", confirming that they were engaging in the act. THAT'S why your friends were laughing :/ What a waste of such a funny phrase.