Hiya!
You kinda hit the nail on the head. The reason your tongue is doing that is because you're narrowing your vocal tract (throat, etc) so much in an effort to "squeeze" the note out that you're extending the squeeze/push up through your "instrument" and into your tongue.

I find that generally anything in the 6's is going to require at least a basic comprehension of whistle tones. All a whistle tone is, is exactly what it sounds like! When you whistle with your lips it's a balance of the position of your lips, the air flow, and the resonance created in your mouth (which is why you can use your tongue to change the notes you are whistling) A SINGING whistle tone is essentially the same thing, it's a balance of how closed/tight your chord is, airflow and upper resonance cavities.

But what does it all mean Bazzle??? How can I whistle??

Well, lets start by dropping the jaw nice and loose-like and pretending we are going to say the letter "A". We hear/feel at the very beginning of the consonant a little "pop", we can feel our chords making a little "kiss". Now comes the imagery. Pretend your chords ARE little lips, relax and pucker up - JUST the chord, not the muscles under it, don't squeese in your thoat above them - focus on the cord, the larynx should still be relaxed, now lets say that "A" (as in Aye or "Long A") again, nice and light and sustain it. Now add a little more support - The jaw should still be open and relaxed, the throat and larynx should still be nice and relaxed - we're feeling NO tension except the Kiss in out chord. Now, as you increase the air pressure and get to a comfortable volume just hold it out there - nice and free.

At this point your probably thinking :but I sound like someone stepped on a mouse!" Now here comes the best part - Open your mouth into a dropped jaw with a smile, lift your palate and open the back of your throat. This adds resonance back in to the weak "mousey tone".

You can also come into it with a quick "h". As you figure out the different balance combinations for the differnt vowels - don't be afraid to modify!

When Jaime speaks of "zipping the cord" the whistle can be thought of as that last little tiny opening before you close the chord - the last little pucker of the "lips". Just remember to balance out the added air pressure with more support of the chord, if the balance is off you will get the same spatter, choppy nothingness you get when you aren't balanced right in a regular whistle.

GL!

Sorry for not getting back to you but THANK YOU for the big post on using whistle!!


I can't wait to try it out myself haha

The thing is C6's and D6's is very very rarely used by even the highest rocktenors. So i dont think focus should be on that, sure play around with it experiment with whistle it's cool.
Whats more important is focusing on getting a cool sound on the C4-C5 after that work on getting awesome on the C5-G5, here there Will still be "singing" going on and not screech effect notes(wich indeed are cool but in the end not something to worry about)

Up around A5-C6's for most males you Will just feel the supportvalue scale like crazy for every halfstep up you take your voice, IF you Imagine yourself surfing around on easy C6's your timbre Will most likely be very hooty soft falsetto bordering on whistle register.

Hope this helps cheers :)