I've found that the most comfortable position for my partner and me is
for us both to have our hand on the other's shoulder blade (that is to
say, on the back rather than the top of the shoulder). Push gently
there and you can get around as fast as you like without either person
getting injured. I never, ever tell the woman to put her hand on top
of the man's shoulder blade. This may be appropriate for ballroom, in
which the woman might have her whole arm draped down the man's with a
bit of tension pressing down, but I haven't seen it work well in
contra unless the woman is experienced enough to dance upright and
bear her own weight. It's a recipe for disaster for a beginner, IMHO,
as is telling her to grab his arm. Beginners panic and start
squeezing, harder and harder, if the swing is fast or they feel
otherwise unsteady on their feet.
When I teach my newcomers' workshop, I include "ways to hurt your partner":
-woman's hand on the top of the man's shoulder, pushing down and
throwing him off balance (draping the hand isn't any better, since
that means he has to support all of her weight)
-Vulcan nerve pinch (same as above but with directed pinching motion
in that soft spot between the top of the shoulder and the neck)
-woman's hand gripping the man's upper arm (gripping harder and harder
if he swings faster)
-woman pushing against the man's chest in an attempt to create
distance (he's having to support her because she really will fall off
otherwise)
-man digging his fingers into the woman's lower back (going for the kidneys?)
-either partner gripping the pointy hand, with or without a pumping
motion (should be either relaxed, loose hold, if you're relying on the
other hand/shoulder blade combo for support) or have light, positive
tension
Then there's all the ways people can position the rest of their bodies
so it's uncomfortable for either or both.
-crab walk (woman is somehow walking backwards; can be fixed by
angling more toward the man)
-man's hand on waist instead of shoulder blade (doesn't help with
balance, can be painful and/or inappropriate)
-woman's chest pressing against the man's arm or body (difficult to
correct without saying "please get your boobs off me" -- and I suspect
many men won't bother correcting this one, either because they're
embarrassed or because they're enjoying it; it's awkward for me to
correct verbally when I'm leading too)
-head down, looking at feet (throws whole frame off and creates dizziness)
-hopping and/or raising knees too high in an attempt at a buzz step
(which is why I demonstrate the buzz step but suggest they keep to a
walking step)
-noodle arms
I'm sure I'm leaving out things, but this is what springs to mind. I
demo some of these bad moves (with exaggeration and humor) when
showing the swing with an experienced partner, then correct around the
teaching circle as needed.
-Marianne