Stone placement

In the early 1970s I learned go from Bruce Wilcox, who was a co-worker at Intermetrics. His technique for placing a stone, using two fingers, caused a nice “click” sound against the board which helped make his play impressive. He tried to show me how easy it was to make the click, but I didn’t practice enough to get it. Perhaps someone in this forum could teach the rest of us how to do that?