Place it just before the left choice appears, then follow it with a bell ding once the option is confirmed on screen. For a game reveal, put an anime wow after the ding to mark the payoff, keeping the prompt first so the choice stays clear.
このサウンドについて
This is a short Japanese spoken instruction, lasting about nine seconds, in which a calm voice politely tells the listener to press the left button. It feels clear, formal and faintly playful, like a helpful cue arriving at exactly the right decision point. The line comes from Million God, where the prompt guides a player toward the left-hand choice.