Usually seen in radio edits, this technique involves reversing sections of a song which contain offensive material. Recently seen on some songs by Eminem. The obvious problem with a flip edit is that the underlying beat is also reversed, and so the beats seem out of sequence. Furthermore, people like me who can never decipher lyrics are more confused by these odd words that appear sporadically.
The next time you're listening to the radio, and you hear "kcuf", "tihs" (more like "tish") or some other mispronounced four-letter word, you are hearing a flip edit.