This technique is for when a person tries to defend your leg lock attempt by stacking you. You do not have to abandon your attack because your opponent goes for the stack. If the person does not know what they are doing they can actually make it easier for you to get the tap.
Reilly Bodycomb goes over a few very important details in the video above. The things he goes over will help you both get the submission and defent it at the same time.
One of the details that stood out to me was that while your opponent is standing up with their heel flat on the ground they are not in danger of being submitted.
