Double Bind is used by sales person as well as in hypnosis. It is basically stating that there are 2 outcomes (by assuming that the person would prefer either one).
Example could be:
“Would you rather have the windows facing the garden or the sea?”
”Would you like to pay by cheque or credit card?”
Statements worded in this manner assumes the other party wants it. It is ‘either’ or ‘or’. Things that fall outside these choices are not included. It gives people as few choices as possible so as to make them come to a decision.