A double squeeze position set up when the double squeeze may, or may not be ‘on’, but which will operate as a simple squeeze. For example:
You are South playing in no-trumps. You lead the ♠A, planning to discard the ♦K from dummy unless West discards the ♦A. Only one opponent can hold four hearts. If this is East and he holds the ♣A too, he will be subject to a squeeze. If West guards the hearts, together with either the ♦A or the ♣A, you will squeeze him.