How to whistle loud with your fingers?

I am trying to whistle with my fingers but i have a few questions.


-Should the air be hitting my fingers when i blow?


- Should i use the method where i fold my tongue back or put my tongue in between my lower teeth?


- Where should i aim the air that i blow?How to whistle loud with your fingers?
For the loudest whistle, tongue up toward roof of mouth, take any finger from each hand touch tongue, blow between both fingers fast and hard.