You do not have to be a skilled whistler to make this work. If you can say "chip or cheese", you can make the bird whistle sing.
Just place the whistle white side down on your tongue with the round to wauds back flat edge to front .make it gently wet for a minute..put it gently up against the palate (roof of your mouth) with your tongue, and blow/say sounds like "TSH..." as in: 'Chips or Chocolate'.
You can clean your whistle by holding it under tap water for a few seconds, dry it in fresh air, and you can use it again whenever you want.
If you want to whistle again, just simply put the bird whistle back in your mouth, wet it a little, and there you go again! With some care you can have endless fun which every single whistle.