Post Mumble is what somebody does after they say something that they think is funny. It consists of a mumble/laugh. It is a repetition of the phrase that was just said. It is usually done by nerds or dweebs.
You look like a hippo! Hwaha youer look lieke aen hippore hhaw haw!! Post Mumble (second Mumble)
by Danny 123561992 September 17, 2008