THE EFFECT: Two borrowed bills are folded length wise. One bill is wrapped around the other, but as if by magic they visually melt through each other.
THE SECRET: Learn the secret below...
Ask for two bills from your audience. Take one bill from them and let them keep one. Ask them to do as do you. First fold the bill length wise, ask them to fold their bill length wise. As they are folding it secretly fold your bill from the center to make an "S" shape. Hide the creases with your finger.
Take their bill from them and fold it into a "V" shape. You should now have their bill as a "V" shape and yours with a secret "S" shape in the middle.
Pretend to put your bill into the folded area but in reality your are inserting the S shaped crease into their bill. Now show that your bill is 'inside' their bill. All that is left to do is to separate the two bills and it will look like one is penetrating the other.
Quickly unfold the "S" shape in your bill and you are left completely clean. Hand both bills out for total examination.
TIP: You can ask the spectator to do the same thing with two bills. It is a great convincer that what you are doing is impossible. They will not be able to separate the two bills without tearing them!