With some whistles, particularly PVC and chrome-plated, when playing with no holes stopped, I sometimes feel the whistle start to slip. I’ve experimented with keeping the right pinky down to brace the whistle. It works, but doesn’t feel natural yet.
Do other players to this?
Yes, I do.
It tends to flop around a bit, as rolls on E and such become odd when the pinky is down, but I keep it down most of the time.
There’s clip of Kevin Crawford somewhere where you can watch his pinky fly willy-nilly from the whistle to the air. I guess it’s just whatever works for you.
Hmmm… I think I do so automatically, and don’t even think about it.
From the conversations on the forum, I think just about everyone uses some finger to brace the whistle on top, particularly when no holes are being covered and at other times too.
I think people often use their pinky if it is long enough to reach. My tutorial recommended it. I have heard some people say that you shouldn’t leave it there because it inhibits the movement of the bottom fingers. I really don’t know about that.
Some people, like me, have a pinky that is too short to reach without bending their hand into a weird position. I keep my ring finger on the bottom hole when I play C# and B. I would keep it there for A and G as well, since it can be handy to have that bottom finger already placed, but on this particular whistle the timbre (I hope that’s the right word) really changes on the A and G when I keep that bottom finger down.
This thread has some stuff in it about holding the whistle (and some other things) that you might find helpful. I think it is an interesting thread, but you may have to pick through it to find answers to your particular question:
http://chiffboard.mati.ca/viewtopic.php?p=490231&highlight=kills#490231
Standard to keep the rt pinky down. Grey Larsen says
do it always. I can’t do it always, but I keep it down mostly.
Another option is rt ring finger, as Cynth describes.
This depends on your whistle, as it may flatten
the tone. On the other hand it facilitates some fingering.
Again on the debit side, sooner or later one may move
to flute, and then it’s not bad to be used to
the pinky down, as that’s pretty standard for flute.
Anyhow, pinky down takes some getting used to,
but it may make a big difference to how well one
plays. Chiefly it’s important that one’s other fingers
aren’t working to steady the instrument. One relaxes
and is faster and less like to get injured if
the whistle is solid before they come down.
I guess it is easy for me because I use the second pads of my right hand fingers rather than the tip pads, so my pinky is just sort of there in position to brace.
I cover the D hole for C# and B. I cover the E and F# holes (but not the D) for some C#'s when going to or from an E , but only in fast stuff.
Actually, he says he lifts it sometimes, especially when using the ring finger. Which is pretty much what I do too. He said this during a workshop I was at. I have an audio recording of him saying it if you need proof to sleep at night.
So… as usual, there are varying degrees to the usage of this little tidbit of finger behavior. 
And as usual… do what works for you, not necessarily what others tell you you should (or shouldn’t) do. 
The more folks you look closely at, the more ways you will see something done.
Right ring finger on the bottom hole works for me.
Having just seem him tonight I can verify this is true. In fact, he turns the foot joint on his Flute so the Eb key is out of the way, well I am guessing that is why he turns it out foward.
I use my pinkie and to brace the instrument, a lot of people do. Some people use the rig on bottom hole.
I just played all my scales… I brace on G - High D, but not on higher or lower notes. Strange, yes? (D sweetone, black, if you must know. :p)
Thanks, all. Very helpful.
I also play oldtime clawhammer banjo, and I frequent the ‘Banjo Hangout’ website also. There, the general advice is the same: ‘Observe what works for others, but don’t be bound to it. There are no rules!’
2 pinkies, 2 thumbs, and mouth. How much gription does one need to overcome the sliptitude?
For me, my pinkie comes down when all of the bottom holes are open. So, basically, if I’m playing G A or B, my pinkie drops.