How to use your whistle?

[garote]

I double on travel calls only....everything else is a single...trying to break the habit but having a heck of a time doing it.

[mick]

My Foxes works just fine.
One tweet always stops play.
mick

[Luis]

I found many double tweet on travelling especially in USA. Personally I only do once and may be multiple for fight(I officiate under FIBA rules, and the book says only blow once...). The most impressive thing to me was that I saw a FIBA ref blowing 10 times very rapidly for a lay-up charging, excellent mouth skill but silly enough like training puppy.