A simple way out of that trap is to self-followup with "Take as long as you want to think it over", or "Do you have any questions about my proposal?", or the ag

A simple way out of that trap is to self-followup with "Take as long as you want to think it over", or "Do you have any questions about my proposal?", or the aggressive "Any objections, or do we have an agreement?" or of course the 21st Century [take out your phone while you wait].