When you do form, do you therefore imagine three unanswered strikes in a row?
It is not a good idea to imagine 3 unanswered strikes. That would be like yang , yang and more Yang without the Yin. when I spoke of exchange, I mention anticipation of a counter attack. If the look at Taiji or yin/yang... for any attack/offense- "yang action" there should be defense or "yin action". so always be prepared for counter attacks of opponent on your offensive movement and vice versa when you defend which is a "yin action" against a opponent attack/offense, be ready to counter/change to offense or "yang action".