Before getting into specific hands and circumstances, I would like to offer a bit of advice relating to falsecards.
DON’T BOTHER WITH THEM!
If this seems like peculiar advice to find in a book on falsecards, well, it is. In general, defense is the hardest part of bridge. It is difficult enough when you know what is going on. It’s nearly impossible when you have to guess. If you insist on sending out a bewildering array of signals, you will nail an occasional declarer or two. But you will also nail your partner. Bridge is a partnership game. One or two or three successes will not compensate for a confused, embarrassed, or upset partner. Ever had this experience?