This article is from the The Complete Guide To Hack Stand-Up Comedy, by Steven Rosenthal and Steve Silberberg (email@example.com) with numerous contributions by others.
Who said that? I can't believe I said that!
Hack says an outrageous line. The line is delivered in such a way that it
sounds like it was Ad-libbed. Hack follows it up with "Did I say that one
out loud?". The audience thinks they've seen the hack says something s/he
didn't really want to, when in fact, the line is cold, calculated, and
precisely inserted in their routine.