Confidence Rating after audio stimuli

For my experiment, participants need to make a decision based on what they just heard (A or B). I also want them to tell me how sure they are about their answer with a 1 to 5 confidence rating. I want them to do this for all the stimuli they hear (approximately 250). What would be the best way to build the confidence rating into my experiment? I tried to present it as feedback but it is too confusing because once the key is pressed the next stimuli plays and you don’t even have time to locate the AB keys.

Within each trial you would have the A or B stimulus, and the event for your confidence rating. What type of participant response are you using for the confidence rating event (mouse, response pad, keyboard)?