Keep it hidden but accessible.
Having the element of surprise at your side may be all the difference you need to thwart a robbery attempt or any other move from your attacker. As they are compact in size, it's quite easy for you to keep them out of view but near enough for you to grab them whenever necessary.
Use it at the right time and place.
Be aware of where you are. Avoid activating your electronic whistle if the area seems too isolated or if you believe you're running low on battery power. Be strategic with its use. Electronic whistles can be an effective but harmless self-defense weapon, but only when you don't panic and use it at the right time and place.