Tarik bibir bawah ke belakang. Posisikan lidah. Tiup udara keluar dari mulut. Sesuaikan lidah dan rahang untuk menemukan titik manis siulan.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
The fingerless wolf whistle is achieved through lip and tongue placement. Push your lower jaw forward slightly. Pull your bottom lip up over your teeth. Your bottom teeth should not be visible, but your upper teeth can be. Your bottom lip should be snug against your lower teeth; if you need help with this movement, press your index and middle fingertip on either side of the mouth to draw your lip slightly out at the corners and over your lips. Draw back your tongue so that it is even with your l